The Treaty of Algeron prohibited the development or use of cloaking technology by the Federation. This treaty was a peace treaty and use of cloaking technology in one's own space couldn't disturb peace. Plus, the Romulans already had cloaking technology, so banning it was unfair for the Federation.
So, why was this ban introduced?

Another thing: There were many things to ban, but why cloaking technology?

  • 3
    Yea, this is a good question. What did the Federation get out of the this treaty?
    – Xantec
    Commented Mar 26, 2012 at 18:11
  • @Xantec Following the memory-alpha link leads to the Tomed Incident which says the Treaty of Algeron "led to the withdrawal of the Romulan government from interstellar affairs until 2364"
    – shufler
    Commented Mar 26, 2012 at 19:51
  • There are plenty of peace treaties in actual human history up to today that restrict technology development by one or more signatories. It's hard to say what the Federation got in return, whether that clause was a precondition of the Romulans, etc.
    – John Feltz
    Commented Dec 18, 2016 at 23:42

6 Answers 6


There was a war waging. While trying to establish the basis of the Federation Earth could not lead a war and tell everyone "We're peaceful" with a straight face. I'm also pretty sure the Vulcans were not too fond of that, either. Mankind was also very young to the Galactic society, I'm sure they didn't like they state with the Romulans. Also don't forget that Earth just outgrew war, and most people most likely did not want to bring 'bad habits' to the stars.

Why the cloaking device was banned is clear. The cloaking device is mostly an offensive technology, you only need a cloak if you want to surprise someone, if you want to surprise someone, you need to shoot first. Additionally the Romulans had that advantage on their side and did not want the Earth to gain that advantage and maybe kick their a...stonishing large ears.

Of course does a cloaking device also have defensive capabilities, but those are very limited. You always have to ask: Why would that guy want to be invisible? Guarding a border with cloaked ships is only good if you want to surprise the enemy in case that it attacks, which means it's again held back for offensive use in the end. You could also just hide their ships to minify possible dangerous situations, but that doesn't really fit well with the motto of the Federation.

It can be basically summed up like this: We're friends unless we screw up or you screw up...and if you develop offensive technology X we'll go all rampage on your foreyard.

  • 3
    Couldn't a shield also be used defensively. "Here comes those really nasty aliens, how can I possibly hide from them?!"
    – AidanO
    Commented Mar 27, 2012 at 8:05
  • @AidanO: Of course, but the Earth/Federation is not exactly the "Uh-huh, here it comes, let's hide" type of people. For a faction which is designated to peace, diplomacy and research there are very limited usages for a cloaking device, at least none I can think of.
    – Bobby
    Commented Mar 27, 2012 at 17:23
  • Cloaking technology would also be useful in avoiding interference with not-quite-ready cultures while still allowing monitoring (and possibly deflecting the odd asteroid or comet). Cloaked mines would also be a largely defensive use of the technology (Yes, a minefield can be used to "surround" an enemy or as a death trap to be driven into or to make the enemy's home territory unsafe [invade, place mines, leave], but like walls they are often viewed as defensive).
    – user11683
    Commented May 15, 2013 at 14:07
  • 1
    @AidanO I'd imagine the shield argument is easier to make, since it also protects against asteroids and whatnot. Also, presumably the Federation already had shields, whereas they did not have cloaking tech. The Romulans could argue the Federation shouldn't develop a new offensive tech, but they could hardly demand that they give up one already in widespread use. Just as nowadays we try to ban nations from creating nuclear weapons, but don't try to take away the anti-air missiles they already have. Commented May 15, 2013 at 14:37
  • @PaulA.Clayton: As far as I know, destroying an asteroid heading towards a non-warp culture would be in violation of the first directive. But as we see in an TNG episode and Insurrection, the Federation already has means to protect them from preying eyes, holograms. Also, using a cloaking device to place mines in front of an enemy or there backyard is a pretty offensive move, too.
    – Bobby
    Commented May 15, 2013 at 14:43

From a military perspective, cloaking technology would be an enormous advantage for offensive, defensive and espionage purposes. No rational state would give it up willingly, and it was certainly within the Federation's technological capabilities to develop it.

This means the Federation gave it up unwillingly. I speculate that the most plausible reason the treaty was signed is that the Federation saw the Romulans as an existential threat. They gave up major concessions to avert a war they viewed as unwinnable.

For reference, here's the relevant chronology:

  • 2266: Kirk encounters Romulan cloaking technology, something previously "considered only theoretically possible, due to the enormous amount of power required.". The device is flawed, and still fairly easy to detect
  • 2268: Romulans perfect the technology, and Kirk obtains a working cloaking device. The device can be run off the Enterprise's power generation capabilities
  • (by 2269): Klingons have cloaking technology.
  • 2286: The Federation obtains a functioning Klingon cloaking device in the events of Star Trek III and IV.
  • 2293: The events of Star Trek VI take place. Praxis explodes, leading to peace overtures and the Khitomer Conference / Accords. By this point the Klingons had developed an enhancement to cloaking technology, allowing them to fire while cloaked (this technology must have proved dangerous, or perhaps been banned in the Khitomer Accords, since it wasn't later used.)
  • 2311: The Treaty of Algeron is signed after the "Tomed Incident", which "was a terrible confrontation between the United Federation of Planets and the Romulan Star Empire in 2311 that cost thousands of lives.". In one of the books, this was apparently a staged event by Star Fleet intelligence to avert a larger war.
  • 2344: In the Battle of Narendra III, the Klingons are betrayed by the Romulans, and the Enterprise C aids them. This leads to an alliance between the Federation and the Klingons. Note that in the alternate timeline, a war with the Klingons takes place, which The Federation was badly losing by 2366.
  • 2358: The USS Pegasus tries a test of dangerous "interphase" cloaking technology. Unlike ordinary cloaking, the technology allowed ships to be completely undetectable.
  • 2368: The Romulans attempt a partially successful test of interphasic cloak. They abandon the technology.
  • 2370: The existence of that the Pegasus test is discovered and publicly revealed by Picard.
  • 2371: An amendment to the Treaty of Algeron is made, which allows the USS Defiant to use a Romulan cloaking device while in the Gamma Quadrant. The device is subsequently used in the alpha quadrant on several occasions in violation of the treaty.
  • 2372-73: The Klingons fight a major war with Cardassia.
  • 2373: The Dominion War starts.
  • 2373: Rom mines the entrance to the wormhole with cloaked mines.
  • 2374: The Romulans are duped into joining the Dominion War by Sisko.
  • 2375: The Dominion War ends.
  • 2395: Date of the alternate timeline in "All Good Things...". In this timeline, the Federation regularly uses cloaking technology, presumably since the Klingons took over the Romulan empire, voiding the treaty.

From the chronology above, you can reconstruct what the balance of power was over time. At the time the treaty was signed, the Klingons and Romulans had a nonaggression pact in place. The Klingons had been severely weakened by the events at Praxis 18 years earlier, which had significantly shifted the balance of power in favor of the Romulans. Given that in the alternate "Enterprise C" timeline, the Klingons were still able to defeat the Federation, in 2311, the Federation must have been badly outgunned.

Additionally, the excellence of Romulan cloaking technology would allow them to use execute genocidal weapons of mass destruction, say by mining the Terran system with cloaked mines or destroying all life on Earth. One can imagine that the Tomed Incident was such a terrorist attack by the Romulans. (Accepting the non-cannon book above, a terrorist attack orchestrated by Starfleet Intelligence, presumably Section 31. They must have realized how badly the Federation was outgunned, and sought to force hardliners to the negotiating table by showing Romulan military superiority, as the US did with Japan in 1945.)

In this theory, the Romulans were afraid the Federation would become a military threat, and were willing to completely annihilate them (including their old enemies, the Vulcans) to prevent it. The Federation was presumably presented with an ultimatum: "cease development of military technology we view as degrading our absolute military superiority to you, or we will conquer the Federation entirely." There were presumably territorial concessions made along the way as well. The Romulans would have felt safe doing this due to their nonaggression pact with the Klingons. No one would stand between the Romulans and domination of the Federation.

Between the Treaty of Algeron and the end of DS9, the balance of power shifted. The Romulans became overconfident, and broke their nonaggression pact with the Klingons. This led to an alliance between the Klingons and the Federation, meaning that the Romulans no longer had absolute superiority.

At this point, in the event of a war with the federation, they would be able to quickly outfit their ships with state-of-the-art Klingon cloaking devices, significantly reducing the Treaty's force. The treaty remained in place, preventing war in the short term, but the Federation began to seek ways of getting out from under its yoke. They developed gravimetric scanners, which meant that the Romulans would no longer be capable of executing a fully surprise attack. They developed better weapons, to the point where their flagship was at least a match for a Romulan warbird. They were still outgunned, but not as badly as they had been.

They attempted to develop cloaks so flawless they could run them without the Romulans knowing they were in violation of the treaty (interphasic cloak). Eventually, the war with the Dominion took precedence, and the Federation began using cloaking more openly, culminating in the cloaked mining of The Wormhole, a major violation of the treaty. The Romulans didn't care, since defeating the Dominion was a higher priority.

That the Federation started using cloaking technology when they were more of an equal to the Romulans militarily is further support for this theory. The treaty existed because the Romulans could credibly claim to be able to force compliance on the Federation if needed. Once that superiority ended, the treaty started to crumble.

  • 1
    This provides a far superior outline and explanation as to why the Federation doesn’t use cloaking technology. Commented Nov 3, 2018 at 12:28

You guys are forgetting something here. Cost, even if the federation doesn't have money there is still a cost to building a ship. Now the federation are already going to more expensive then their romulan or klingon counterparts do to the scientific instrumentation and the very long range capabilities they possess. The romulan and klingon ships have neither of these. Now one can imagine that you need lots of energy and some pretty exotic elements and components for a working model. Not to mention the model we see in TOS only covers visible light. In other words these are expensive pieces of gear with serious tactical draw backs and adding these to your whole would seriously impact your ability to produce ships of the line. That ability that will determine the outcome of the war, where as cloaking your ships will going you the element of surprise, until they figure out how to detect and catch your entire fleet cloaked.

  • How does adding a cloak contribute to a substantial increase in the cost of developing a ship? Although the physics is tricky, the cloak itself seems quite inexpensive.
    – Valorum
    Commented Jul 7, 2014 at 7:40

I dont really feel these answers so far are at all accurate. Cloaking could be employed in so.many defnsive situations, which is what brought me to ask myself the question op posed to begin with. Image in you had to pass by the borg? Or a fleet of romulan vessels, etc etc. Conflict avoidance is often very important. Also as earlier stated by someone else, there can be anthropological applications. Plus in times of war, it could be invaluable.

In addition, as far as production cost goes, its a fictional story! They could easily work in some reason as to how it could be afforded.

The real reason, as far as I can tell is NOT any of the previously proposed reasons, but rather simply due to the fact that Star Trek is fiction. Those writing it probably wanted to create enemies that had some intimidating upperhand factors, in order to make things interesting.

So they wrote in treaties, etc into the story that would offer some minor explanation, but honestly, the reasoning I have heard from the treaties and other fans seem quite fallible. In order to defend them they have to resort to reasoning that only recognizes half the facts. C'est domage

  • 3
    We all recognize that the real answer to most of our questions is "because it made a better story". Those aren't interesting answers. We also like to think that the writers were smart enough to explain their universe to us -- that's the kind of answers we're looking for here.
    – KutuluMike
    Commented Jan 31, 2016 at 12:16

What technology/knowledge does the Federation have that the Romulans don't? Time-travel. Completely speculative on my part, but my theory has always been that the Federation would give up researching cloaking technology in return for the Romulans not pursuing time-travel.

  • 2
    Eh? I thought the Federation (in general) actively avoided time travel? Commented May 15, 2013 at 10:12
  • 2
    @pauld.waite - Not in the early stages of TOS.
    – Valorum
    Commented Jul 7, 2014 at 7:38
  • @Richard: true true. Commented Jul 7, 2014 at 9:07
  • @PaulD.Waite - Still a bad answer though.
    – Valorum
    Commented Jul 7, 2014 at 9:47
  • 2
    @pauld.waite - especially given that the Romulans power source seems to lend itself to time manipulation.
    – Valorum
    Commented Jul 7, 2014 at 10:27

The Romulans broke off from the Vulcan Empire I believe. Back in the day the Vulcans were an overly passionate, strong emotioned destructive people. They almost destroyed themselves. until Surak who they considered the father of their ways, came up with logic. Vulcan changed and some of the people did not agree. Spocks own half brother Sybok did not believe in logic.

The people who left Vulcan found their own world and came up with their own ways. They eventually came to be known as the Romulan Star Empire. They retained their roots. And over time those roots have multiplied and became a race of beings similar to the Vulcans but instead of logic, they have the same drive that they are better and their ways are better. Romulans think they are the superior race. They do not mind lying to beings they consider to be less then they are. They are hypocrites. Hence forth a General mating with Tasha Yar. They are conniving, Even friends gained over the years, they wont hesitate to betray, like Spock and Pardak. Pardak knew Spock for 80 years, yet he betrayed him. As Spock accused him, he sat there in self righteousness, lying, till Sela came out and said the jig was up. Then when he left he simply said goodbye to Spock not even ashamed of being caught.

What was the first contact we experienced with the Romulans? They destroyed outposts purposely because they had superior firepower and a cloaking device. In that early episode their cloak was detected as they wandered through Federation space, and their weapons had a range limit. They came out to test this with the idea of starting war with the Federation. They were defeated. This ruined their plans for going to war with the Federation. The only theory I can come of up is because of their mistrustful nature they only would assume that the Federation would do the same thing they tried to do if they had cloaking technology. It's a given that 50 percent of the time at least people who do not trust anyone usually cannot be trusted. This is how the Romulans think.

With cloaking technology the Federation would be a problem. The Federation usually wants peace, so when the Romulan Empire added that clause, and more than likely did not hide the fact that they did not trust the Federation, when the treaty was being made, the Federation did not pursue the technology and kept to the treaty so they would have nothing to worry about in Romulan Space. We know parts of Starfleet Intelligence did in fact try to secretly develop a cloaking device in the 24th century, failing on the Pegasus, but working on the Enterprise. They were caught and charged, almost ruining Riker's career. So if the Federation did knowingly pursue the technology and the Romulans found out then it would be the Federation that broke the treaty and started the war in the eyes of the known universe. The Romulans always tried to look like they were righteous and the good guys and would not hesitate to kill their own people to keep that illusion, not to be the ones to start war, as they did in Unification when they destroyed their own ships heading to Vulcan.

What it comes down to is that through their own actions the Romulans come off to most other races as sneaky, not to be trusted, stab you in the back beings that don't trust anyone.

  • Could you format this a bit?
    – Adamant
    Commented Jul 23, 2016 at 8:39
  • no I don't think so. I actually just wanted to ask one question on google the other night and it lead me here. I had to join to answer and give my opinion. Now I see clicks forming here already. My explanartions are sound but you down vote me or whatever you did to get me to -1 and others have deleted my comments. This site is clickish and I'm not really interested in formats or how other people wants things. Seems like a way to control for a bunch of nerds who want to rule a situation. Badges and crap like that. No thanks.
    – Newhouse75
    Commented Jul 23, 2016 at 10:23
  • 1
    Well, I was not one of those who downvoted you. I prefer to give people an opportunity to improve decent-quality answers before downvoting. I would point out that formatting an answer is not a means of exerting "control"; rather, answers with really good formatting are easy for people to read, particularly non-experts, whereas the reverse is true for non-formatted answers.
    – Adamant
    Commented Jul 23, 2016 at 20:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.