This photo released by Rutgers University Press shows the cover for "Strange Bedfellows-How Late Night Comedy Turns Democracy into a Joke'" by Russell L. Peterson. (AP Photo/Rutgers University Press) ** NO SALES **

Ask a 30-something to impersonate George H.W. Bush, and chances are you’ll get the “Saturday Night Live” version – an imitation of former cast member Dana Carvey nasally intoning, “Not gonna do it,” or “Wouldn’t be prudent.”

As time passes, the senior Bush will be remembered more by those Carvey impressions than for his actual accomplishments, suggests Russell Peterson, a former standup comic who teaches American studies at the University of Iowa.

That’s just one example of how late-night comedy can influence the way we think of, and remember, our political figures, he writes in “Strange Bedfellows: How Late-Night Comedy Turns Democracy Into a Joke” (Rutgers University Press, $24.95). It’s a trend that leaves him concerned.

With restrained patience, Peterson blames the current crop of network late-night comedians – Jay Leno, David Letterman, Conan O’Brien and numerous casts of “Saturday Night Live” – for stirring up cynicism about our political process.

Leno, Letterman and O’Brien in particular strive to be equal-opportunity offenders, meaning they mock Democrats and Republicans equally. But the result, Peterson argues, is that audiences lose respect for both parties equally instead of just blaming specific politicians for specific failings.

In other cases, truth gets trumped for comedic purposes. For example, Al Gore became a frequent target of comics after he allegedly claimed he invented the Internet. The only problem was, he never said that, exactly.

What he said was that as a member of Congress he “took the initiative in creating the Internet” – an awkwardly worded statement, yes, but not a claim of personal invention. Yet when an unsigned press release from the Republican Party exaggerated the invention claim, comics irresponsibly ran with it instead of verifying its accuracy.

But that’s how late-night comedians do their job, Peterson laments. They dig for humor by reducing politicians to one-dimensional caricatures and consistently harping on those narrow themes. So we get barraged by jokes of George W. Bush as half-witted, Hillary Rodham Clinton as cold, John Kerry as boring and Al Gore as eager to take credit for inventing everything.

Peterson sees hope, however, with the latest generation of comedians and the cable shows they host. Jon Stewart and Stephen Colbert rely more on satire than humor, so they make a real point about political flaws instead of simply calling attention to them for a cheap laugh.

“Strange Bedfellows” will appeal more to left-leaning readers. Stewart, Colbert and Bill Maher are lauded as courageous speakers of the truth, while right-wing figures such as Rush Limbaugh, Ann Coulter, Bill O’Reilly and Dennis Miller are mentioned only in passing and with barely concealed contempt.

Peterson makes compelling arguments, supplementing his points with a number of comedic nuggets. But the book frequently veers off target, for example, with lengthy treatises about Walter Cronkite and Johnny Carson that seem more nostalgic than educational.

He also digresses into specific critiques of some late-night hosts, tracing how their jokes have grown increasingly off-color following the Monica Lewinsky scandal. It’s interesting but not related to the democracy angle promised in the subtitle.

Overall Peterson doesn’t break much new ground and the points are based more on anecdote than scientific analysis. His book still makes for a satisfactory read, but its subtitle makes readers expect something different.

Because the book focuses on more than just the comedians’ effect on democracy, a better title may have been, “Strange Bedfellows: The Birth and Development of Late-Night Comedy.”