To paraphrase Mark Twain: Suppose you’re an imbecile. Now suppose you’re Howard Dean. Oops, I repeat myself.

Dean, the Democratic Party boss with the say-anything habit, has outdone himself with his newest foray into fantasy. As usual, his idea is wrapped in false packaging and sealed with slimy innuendo. Here are a few of the whoppers he recently let loose on San Antonio, Texas, radio station WOAI:

The “idea that we’re going to win the war in Iraq is an idea which is just plain wrong.”

“This is the same situation we had in Vietnam. Everybody then kept saying, ‘Just another year, just stay the course, we’ll have a victory.’ Well, we didn’t have a victory, and this policy cost the lives of an additional 25,000 troops because we were too stubborn to recognize what was happening.”

“What we see today is very much like what was going on in Watergate. It turns out there is a lot of good evidence that President Bush did not tell the truth when he was asking Congress for the power to go to war.”

Vietnam. Watergate. The kitchen sink. His M.O. is apparently to think of the worst things you can say _ then say them, facts be damned. But as rancid as his false links to the past are, Dean’s plan for the future is downright dangerous.

“I think we need a strategic redeployment over a period of two years,” Dean said. “Bring the 80,000 National Guard and reserve troops home immediately. … We ought to have a redeployment to Afghanistan of 20,000 troops, we don’t have enough troops to do the job there and it’s a place where we are welcome. And we need a force in the Middle East, not in Iraq but in a friendly neighboring country to fight (terrorist leader Abu Musab al-Zarqawi), who came to Iraq after this invasion.”

Thank God Howard Dean is not president. Virtually every idea in that paragraph is either false or nuts. But this is the gist of the wackadoo wing’s big lies — that terrorism is a direct outgrowth of the Iraq invasion and that Iraq was a workers’ paradise before we showed up in our jackboots.

Fact: Terrorists attacked Americans repeatedly before the war. As for the prewar conditions in Iraq, Dean & Co. should try their rosy vision on the survivors of Saddam Hussein’s torture chambers risking their lives to testify against him.

The only risk Dean is taking is that he’ll lead the Democratic Party over the cliff. That is what will happen if the rank and file rallies round his idea.

Dean misreads the understandable public discontent about Iraq as a license to spin fiction and promote retreat. In the process, many Americans will remember why they haven’t trusted Democrats on security issues for two generations. To wit, Dems are seen as the party of butter only and as soft on defense.

And so while Sens. Hillary Clinton and John Kerry try to distinguish themselves from Bush without actually calling for withdrawal, Dean’s rant stamps them as members of the party of retreat.

One more thing: He says his cut-and-run plan is a “strategic redeployment,” not a withdrawal.

And he has the nerve to call Bush a liar.

Michael Goodwin is a Pulitzer Prize-winning columnist for the New York Daily News, 450 W. 33rd St., New York, N.Y. 10001; E-mail: Mgoodwin@edit.nydailynews.com.