THE BIG JOKE in Washington these days is that the 9 percent of survey respondents who don't give George Bush a favorable approval rating are all considering running for the Democratic nomination.

Judging from most of the recent pre-election commentary, this is not much of an exaggeration. Very few people seem to think Bush can be defeated in 1992. The solid Democratic base of Blacks, liberals and the aged will deliver about 40 percent of the votes to the Democrats. Depending on the savvy and skill of their candidate, another 5 to 7 percent may fall the Democrats' way. But Bush basically has it locked up. So goes the conventional wisdom.

And it's never been sillier.

IN LAST SUNDAY'S Boston Globe, Martin F. Nolan even trotted out some nonsense suggesting that George Bush could inaugurate a second "era of good feelings (a la James Monroe in 1820) by naming Democratic Sen. Albert Gore Jr. '69 of Tennessee as his '92 running mate. Time Magazine ran a bizarre piece last week proposing that the Democrats nominate Bush with a Democratic running mate. The pundits are desperate for a story.

But George Bush is not invincible. In fact, those within the reelection campaign hierarchy fear a Democratic surprise. William B. Lacy, who ran the successful Bush campaign in California in 1988, said this week that the Democrats can bounce back in '92. And Bush is still having problems in Washington.

Just two weeks ago, Gen. H. Norman Schwarzkopf dropped a bombshell when he questioned Bush's decision to keep the war out of Baghdad. Democrats have much to gain from jumping on the "Save the Kurds" bandwagon. Bush's reputation as a foreign policy guru should last about as long as the Kurds did against Saddam's helicopter gunships.

Such behind-the-scenes wrangling is reminiscent of last fall, when many Republicans refused to return one another's phone calls over the budget debacle. Bush's turnaround on taxes and his poor handling of party infighting dropped his approval ratings and wilted people's faith in his ability to negotiate Washington battles.

Any political junkie will acknowledge that a year in politics is an eternity. George Bush will not be allowed to fight the war straight through 1992. A long war could have been great for the president--it would have kept the electorate's mind off the deficit, the recession, higher taxes. But, thankfully, the war was short, and now is the time for Democrats to attack.

THE ATTACK must be quick and ruthless. If the Democrats really want to win the White House in 1992--and they can--they must craft a strategy something like the following:

Kick out the liberals before the primaries. As much as I hate to admit it, District of Columbia "Shadow Senator" Jesse L. Jackson and Gov. Mario M. Cuomo of New York will not win the 1992 election--not by a long shot. Nominating one of them--or, even worse, the persistent George McGovern or the laughable Paul E. Tsongas--will doom the Democratic Party to another four years of "Don't forget--we control the Congress." A national party needs a nationally unifying leader.

The Cuomos and the Jacksons in the Democratic Party don't fit the bill. Most Americans--including most Democrats--consider them tax-and-spenders who care more about minority rights than about majority government.

Unfortunately, Democratic primaries tend to attract diehard liberals, who tend to nominate liberal candidates. When the general election comes around, more conservative Democrats come out to vote--and choose the Republican nominee. So...

Nominate someone with a conservative image. The most logical choice right now is Gore. While the Gulf War will not decide the '92 election, it will be important. Since Gore voted to grant Bush war powers in January--a vote that has gained enough symbolic value to make a 1992 bid impossible for Mr. Sanctions, Sen. Sam Nunn (D-Ga.)--he can neutralize charges that Democrats would have appeased Saddam Hussein.

A good running mate for Gore would be Nebraska Sen. Bob Kerrey, whose Congressional Medal of Honor and loss of a leg in Vietnam would preempt any perceptions of softness on national defense. His "down-home" Midwestern image will retain the Democrats' traditional strength in Minnesota and Michigan.

Washington outsiders could also serve the Democrats well, as Jimmy Carter did in 1976. Virginia Gov. L. Douglas Wilder, has already formed a committee to test campaign waters. Arkansas Gov. Bill Clinton, who almost entered the '88 race, should probably run as well to build name recognition. All four of these potential nominees support the death penalty, a morally repugnant position that is unfortunately necessary to win an election in today's political climate.