Why did the Jedi take the clone army without further thought?

Question

In The Attack of the Clones film, the Jedi find out about an army that was apparently ordered by a mysterious Jedi, without authorization of the Jedi Council. They don't know what he ordered it for, or how it was paid. That definitely should sound strange. Besides, the Jedi know someone else was involved (Jango tells Obi Wan that he was recruited by someone called Tyranus).

Weren't those reasons enough to make the Jedi suspicious about that army? Why did they just grab the army and use it right away? I'm not saying they could have anticipated Order 66 specifically. And it's true that the Jedi were in a position in which they needed an army. But they should have known to be very careful about something with such a dubious origin, right? How is it that they just took the army without hesitation?

TL;DR

Why did the Jedi take an army whose creation had not been approved or even supervised by the Jedi Council? It was obvious that an army with such unclear origin might have some catch.

Answer 1

The very essence of the Clone Wars is that it was a gigantic hoax, designed to garner Senator Palpatine great power and to place the Jedi into a position where they would be at their weakest and most vulnerable for a millennium.

When the extent of the Separatist's 'Droid Army' (e.g. millions of droids) becomes apparent, the Senate panics and decides that they'll use the Clone Army to defend themselves. Note that at this point, although the Jedi are mightily confused about who ordered the army, they're under no illusions about the loyalty of the Clones (who they see have been indoctrinated from birth to blindly serve the Republic).

The Attack of the Clones novelisation gives us some behind the scenes info about what was happening back on Coruscant while we were watching Anakin, Padme and Obi-wan:

Everyone listened carefully to Mace Windu’s summary; then Bail Organa shook his head. “The Commerce Guilds are preparing for war — there can be no doubt of that.” Yoda’s ears twitched. Listen, these Senators did not. They feared, and reacted. They did not think.

“Now we need that clone army!” Senator Ask Aak burst out.

But everyone knew the Senate would never give its approval for that — not until it was too late. And there were not enough Jedi to hold off an army of droids.

“Through negotiation, the Jedi maintains peace,” Yoda said pointedly. “To start a war, we do not intend.” There might, even yet, be time to talk a way out of the conflict … but he sensed no patience in the room, only fear and urgency as the Senators discussed what to do.

“The Senate must vote the Chancellor emergency powers,” Mas Amedda suggested at last. “Then he could approve the use of the clones.”

Obviously, we now know that Tyranus was in fact Darth Tyranus (AKA Count Dooku), that the army was in fact ordered by the Sith as a trap for the Jedi and that they were implanted with bio-chips that made them utterly obedient to the Chancellor. But at the time, none of this was in the least bit apparent to the Jedi or the Senate.

Answer 2

Two things:

For one, Obi-Wan in AOTC only hears the name "Tyranus", with no indication that this person is a Sith. Sure, it sounds like an "evil" name to our ears - but in general, and especially in a vast, pluralistic society such as the Republic, comprising many different cultures and races, you really wouldn't be able to judge someone's character by the presumed evilness ( or lack thereof ) of the sound of their name. I mean, you don't get to pick your name. Well, some people do, but you know what I mean. For all we know the kindergarten classrooms on Coruscant are filled with little Tyranuses.

In what is now Legends-canon, circa 2005, Yoda believed Tyranus to have been on the side of the Republic:

"By someone on the side of the Republic, chosen he was on Bogg Four to be the clone template." ( Yoda, Labyrinth of Evil )

Also, from the Jedi POV, Sifo-Dyas - one of their own - might have been involved in the creation of the army, or at least in making the initial contact with Kamino and placing an order. That this would have to have been done in "rogue" fashion is certainly significant, but we have precedent in Qui-Gon for Jedi sometimes acting independently of the Council or going against the Council's wishes. It's not unheard of. And for all we know Sifo-Dyas might have done something like this before, in response to Force visions or whatever other reason. Certainly the Jedi in AOTC seem doubtful but it is important to remember that Sifo's involvement is never disproven during the film, Obi-Wan's impressions notwithstanding.

Going back to Labyrinth of Evil, it was revealed in that text that Yoda returned to Kamino and found apparent evidence of Sifo's involvement:

Obi-Wan turned to face Yoda. "Master, did Sifo-Dyas order the clone army?"

Yoda nodded. "Contacted the Kaminoans, he did."

"Without your knowledge?"

"Without it, yes. But exists, a record of his initial contact." ( Labyrinth of Evil )

By the time the Jedi learned of the existence of this army, they needed it. The clones came to the rescue of many high-ranking Jedi on Geonosis and thus hardly looked like a threat to the Jedi at the time.

[ Of course, as is its wont, The Clone Wars made the situation significantly more problematical, by revealing to the pre-ROTS Jedi that Tyranus was Dooku, that Dooku was involved in the creation of the clones, and that the clones had a secret implanted chip prone to potential malfunction! Not to mention Yoda getting a vision that showed clones attacking Jedi! SMH. ]

Answer 3

You have to remember the Jedi were some what blind to what was going on. They couldn't even sense the Sith on their door step. So even though it's all perfectly clear to us it wasn’t to them.