The ancient imperial capital conjured in HBO's recently expired series, Rome, was full of dark intrigue, treachery and gruesomely memorable characters. But it had nothing on Washington, our Rome on the Potomac. I'm not speaking only of the reign of mad Emperor George, but also about Washington in President Kennedy's day. Beginning with the Bay of Pigs - whose CIA planners Bobby Kennedy later called "treasonous" for seriously contemplating ignoring the president's orders - a poisonous air began wafting through the capital. Top generals, spymasters, far-right congressmen, defense industry lobbyists and anti-communist zealots all began muttering about the young man in the Oval Office, who, in their minds, was weak and inexperienced and had failed his first test as commander-in-chief. "Mr. Kennedy was a very bad president," Admiral Arleigh Burke, head of naval operations, concluded. "He permitted himself to jeopardize the nation." This was one of the more temperate remarks about the young president coming out of military quarters. General Curtis LeMay, the cigar-chomping Air Force chief - a man whom JFK considered seriously unbalanced for his blithe talk about nuclear war with the Soviet Union - was more vitriolic about Kennedy and his circle, snarling that they should have been crushed "like the cockroaches they were."

One of the most eye-opening discoveries I made while researching my book was how bitterly divided the Kennedy administration was - it was a government at war with itself. JFK -- who was increasingly isolated from his top national security advisers in the Pentagon, CIA, and even White House - clearly sensed the mutinous mood in some corners of Washington. In conversations with friends, Kennedy raised the specter of an assassination or coup with disturbing frequency during his brief presidency.

In 1962, Kennedy took the extraordinary step of reaching out to liberal friends in Hollywood, asking director John Frankenheimer to make a movie version of Seven Days in May, the best-selling political thriller about a military coup that nearly topples a pro-peace president. "Kennedy wanted Seven Days in May to be made as a warning to the generals," Arthur Schlesinger Jr. told me before his recent death. But JFK also wanted to wake up the American people to the growing threat against democracy.

There is something very poignant about this. Today Kennedy is regarded as a supremely self-confident leader who ran his administration with poise and charm. But the true inner life of the Kennedy presidency was much more tumultuous than this. So embattled was the president of the United States that he felt compelled to appeal to a Hollywood director to help him keep his dangerously disgruntled military in its proper place.