A danger when reading William F. Buckley's spy novels is that we can't help but wonder if his stories are not, maybe, more than entertainments. The adventures of charming Cold War warrior Blackford Oakes smack of reality, insider knowledge and hushed political secrets.

Take, for example, "Tucker's Last Stand," Buckley's latest. Odds are if you settle back for an evening or two with the book you'll say at the conclusion, and possibly aloud: "So that's how it really was." And who can blame us for thinking we're getting a glimpse behind the scenes, beyond the now-yellowed headlines of 1964, a presidential election year, when America was slowly sinking into the bog of the Vietnam War?Especially since the novel is peopled with a notable number of real-life players - LBJ, Bobby Kennedy, Barry Goldwater, Ho Chi Minh and a host of their allies and minions. These 1960s icons aren't just hovering in the background, either. They converse, argue, think and plot before our eyes:Lyndon Baines Johnson was morose. He sat there in the Cabinet room with his closest aides - McNamara, Bundy, Rusk, Rostow, and also Valenti and Moyers. They had all seen him in such condition, but rarely. When it happened, the vitriol reigned for the initial period, and then, eventually, he would focus his powerful mind on the vexation, the irritant, the . . . creating the problem! His sense of maneuver would then awaken, and he would rise from despondency to a cathartic kind of torrential abuse - after which order imposed itself on his thinking. Then would come the planning.Buckley's haughty-nasal enunciation echoes in the mind when we read passages like that, doesn't it?

"Tucker's Last Stand" unfolds marvelously when Buckley re-animates the political ghosts of the 1960s; the covert operation that's ostensibly at the novel's core is intriguing as well. Oakes, spy-master Rufus and a capable but guilt-laden genius named Tucker Montana, you see, are trying to stem the tide of men and materiel seeping down the Ho Chi Minh Trail through Laos into South Vietnam.

This is the ninth Blackford Oakes yarn, and it's to Buckley's credit that he has managed to weld recent history and tall tale so well for so long. No one writes spy novels quite like him. The first, "Saving the Queen," now seems more of a lark, but the novels since have been cheeky yet insightful escapades.

We just have to remember, this is fiction, not fact. Isn't it?