I'm looking for a book where a man develops a new laser weapon but then has to deal with the politicians in Washington and all the complex against him.
Committee of the Whole by Frank Herbert. Previously identified in Looking for story about man on televised trial, presents plans for laser gun
The main character is William Custer. He is called to a hearing in Washington:
With an increasing sense of unease, Alan Wallace studied his client as they neared the public hearing room on the second floor of the Old Senate Office Building. The guy was too relaxed.
"Bill, I'm worried about this," Wallace said. "You could damn well lose your grazing rights here in this room today."
Custer reveals that he has invented a laser that can be built at home and is so powerful that:
"Powered by less than two hundred volts, this device could cut our planet in half like a ripe tomato," Custer said. "One man could destroy an aerial armada with it, knock down ICBMs before they touched atmosphere, sink a fleet, pulverize a city. I'm afraid, sir, that I haven't mentally catalogued all the violent implications of this device.
The story is unashamedly libertarian. The underlying idea is to take power out of the hands of politicians and return it to the common man. The story ends:
"The revolution begins," Custer said. He waved a hand as the Senator started to whirl away. "Sit down, Senator."
Wallace, watching the Senator obey, saw how the balance of control had changed in this room.
"Ideas are in the wind," Custer said. "There comes a time for a thing to develop, it comes into being. The spinning jenny came into being because that was its time. It was based on countless ideas that had preceded it."
"And this is the age of the laser?" Tiborough asked.
"It was bound to come," Custer said. "But the number of people in the world who're filled with hate and frustration and violence has been growing with terrible speed. You add to that the enormous danger that this might fall into the hands of just one group or nation or . . ." Custer shrugged. "This is too much power to be confined to one man or group with the hope they'll administer wisely. I didn't dare delay.
That's why I spread this thing now and announced it as broadly as I could."
Tiborough leaned back in his chair, his hands in his lap. His face was pale and beads of perspiration stood out on his forehead.
"We won't make it."
"I hope you're wrong, Senator," Custer said. "But the only thing I know for sure is that we'd have had less chance of making it tomorrow than we have today."
There are probably a number of books that might fit this description. However, the one that immediately jumped to mind for me was Slan by A. E. van Vogt. It concerns a boy with an invention that lets him shoot energy beams; however, his (telepathic) type is being hunted by the government, and he gets involved in both violence and intrigue.
The plot summary, per Wikipedia:
Slans are evolved humans, named after their alleged creator, Samuel Lann. They have the psychic abilities to read minds and are super-intelligent. They possess near limitless stamina, "nerves of steel," and superior strength and speed. When Slans are ill or seriously injured, they go into a healing trance automatically.
There are two kinds of Slans. One has tendrils and can read the minds of ordinary humans and telepathically communicate with other Slans. The tendrils are golden in color, making it easy to spot a Slan. These Slans are hunted to near extinction. The other type of Slan is tendrilless. They are still super intelligent but do not have psychic capabilities, only the ability to hide their thoughts from the first type of Slan. Kier Gray is the leader of the human society and vows to exterminate the Slans.
As the novel begins, nine-year-old Jommy Cross (a telepathic Slan of the first type) is brought with his mother to the capital, Centropolis. They are both discovered and Jommy's mother is killed. Jommy manages to escape. Jommy Cross is not only the heir to the brilliant inventions of his father, but he represents the last hope of his race to save it from genocide. Because of the importance of his mission, he is opposed by various enemies. Jommy seeks to destroy Kier and in confronting him discovers an astonishing secret.