For the time being, the United States has a parliamentary system. The fate of the president is in the hands of Congress, and the fate of Congress is in the hands of the voters. Will the midterm election be interpreted as a referendum on impeachment? Of course it will. Even if most voters don't intend it to be.

Suppose Republicans win a huge victory next month, the kind of victory some of them talked about in the giddy aftermath of President Clinton's Aug. 17 confession--a gain of at least 20 House seats and five Senate seats. That would give the GOP a total of 60 Senators, enough to cut off filibusters and control the debate.

That kind of victory would be taken as a mandate to impeach, even if opinion polls show most Americans continuing to support the president. The only poll that counts is the one on Election Day, remember? Democrats would probably press the president to resign, to keep him from doing further damage to their party in 2000.

Be prepared for the argument that the election results are ''biased.'' These days, after all, barely a third of the eligible voters turn out to vote in a typical midterm election. If Clinton-haters turn out in large numbers, as expected, while demoralized Democrats stay home, the result could be criticized as a distorted picture of the preferences of the American public. The public wants Clinton in. Voters want Clinton out. Who should prevail?

The answer is the voters, and for a very good reason. Election results are weighted by intensity. Poll results are not. Polls count noses. Elections count people who feel strongly enough to bestir themselves to vote. If Clinton-haters feel so strongly that they vote in large numbers and Clinton-defenders don't particularly care, should members of the two constituencies be counted equally?

That's exactly why all but five House Democrats voted to proceed with some form of impeachment inquiry, even though the polls showed most Americans opposed. The calls, letters, faxes and e-mails coming into congressional offices ran strongly against the president. Those kinds of communications are weighted by intensity, just like election results, and thus can be a more reliable indicator of what's likely to happen in a low-turnout election than polls can. At least, that's what Republicans are counting on.

Before Clinton's confession, Democrats sounded pretty giddy about their prospects this year. They believed they had a serious chance of picking up the 11 seats they need to recover a House majority. That was always a bold claim, given the fact that the president's party almost never gains House seats in a midterm election. If Democrats were somehow to defy history and make gains on Nov. 3--any gains at all--it would be seen as an enormous victory for Clinton. And a mandate against impeachment.

The most likely outcome is somewhere in between-- Republican gains falling short of 10 House seats and five Senate seats. Then it would become a game of exceeding expectations. So both parties are rushing to set them as low as possible. ''Let's get expectations back into focus,'' Democratic Party Chairman Roy Romer said last month. ''The average loss of seats by the party that had an incumbent president was 22 in an off-year election. When you are in the sixth year, my memory is it's 35. These are normal trends.'' Yes, but this is not a normal year. Losses of that magnitude--given Democratic expectations a few months ago-- would be seen as catastrophic.

Several key races will serve as markers. No one will be surprised if Carol Moseley-Braun, a one-term Democrat, loses her Senate seat in Illinois. She's looked vulnerable for the past six years. But if two West Coast Democrats, Barbara Boxer in California and Patty Murray in Washington, go down to defeat, the message is likely to be: Clinton did it. Particularly if Boxer takes gubernatorial candidate Gray Davis down with her.

What if GOP Sens. Alfonse M. D'Amato of New York and Lauch Faircloth of North Carolina go down? Same message: Clinton did it. Only then, he'd look like a hero to Democrats.

Republicans are quietly getting the word out to their base: This election is a referendum on Clinton. Democrats, on the other hand, do not want to call it that. They don't want to energize the anti-Clinton vote. They prefer to see the election as a referendum on the Republican-run Congress. Former White House counsel Lanny Davis posed the choice this way: ''The Republicans want to keep this matter going for their own reasons, way beyond what would be necessary to hold the president accountable for his unfortunate conduct, versus the Democrats, who are willing to find some resolution that would hold the president accountable and bring this matter to a close. Which do you prefer?''

One thing is clear: Triangulation is out. Clinton's fate depends entirely on how well congressional Democrats do on Nov. 3. ''We need a Democratic Party with a common agenda for the 21st century,'' Vice President Al Gore said. ''Saving Social Security first, investing in education, a patients' bill of rights, a cleaner environment, opportunity for all. That's the agenda we must carry to victory in November.''

These days, it's not enough to win the election. You also have to win the interpretation. When impeachment is at stake, the interpretation is crucial: Will the outcome be seen as a mandate for or against impeachment? The president's fate hangs on the answer.

William Schneider is a resident fellow at AEI.