Tom Clancy's Divide and Conquer (Op-Center #7) by Jeff Rovin

"Shadowy elements within the State Department secretly cause tensions to flare between Iran and the former Soviet republic of Azerbaijan. They hope to start a shooting war to increase their own power and profit. At the same time, the conspirators decide to up the ante - by deposing the president of the United States. In a treacherous scheme, they convince the president that he is mentally unstable, and a silent coup d'état is within their reach. Now, Paul Hood and the members of Op-Center must race against the clock to prevent the outbreak of war, save the honor of the president - and expose the traitors."