(FORTUNE Magazine) – So it looks as if we're going to have Bill Clinton to kick around for a while. But the longer he stays at the White House, the fewer Democrats who are likely to remain in Congress. The President's sexcapades have demoralized and demobilized his party's rank-and-file while energizing the Republicans'. As a result, the midterm election in November will probably provide a runaway victory for the GOP.

That would be a stunning reversal. A mere two months ago the Democrats looked sure to gain a few seats in the House and stay even in the Senate. Democrats were so optimistic that they launched an ambitious, nationwide fundraising drive, the main draw of which was to be...President Clinton. Oops.

Now the Democrats are expected to lose ground, perhaps substantially, in both houses of Congress. The nonpartisan Cook Political Report predicts that Republicans will gain between ten and 20 seats in the House and between three and five seats in the Senate. A five-seat gain in the Senate would give the GOP a filibuster-proof majority of 60 seats, which means that Dem-ocrats would be unable to stop legislation from coming to a vote. In effect, Democratic lawmakers would be powerless to affect the most important issues of the day.

Democratic pollsters argue that the decline in the party's prospects really has little to do with Clinton's ignominy. A few Democratic incumbents were already in trouble because of their own failings, such as Sen. Carol Moseley-Braun of Illinois, who has been accused by critics of campaign-finance irregularities. Indeed, the Lewinsky affair is so distasteful that the Republican National Committee doesn't mention it in fundraising solicitations.

But don't be fooled: Democrats are feeling the President's pain. "Everywhere we're polling we're getting happy numbers," Republican pollster Bill McInturf says. "In the places where we were behind, we're behind by less. Where we were ahead, we're ahead by more. We've had a very happy few weeks." And GOP grins will get wider the deeper the President descends. With every dip in Clinton's popularity, a few more Democrats move onto the endangered list. In the Senate, Harry Reid of Nevada and Barbara Boxer of California are already in trouble. Russ Feingold of Wisconsin and a whole slew of House Democrats will fall into the same category if the scandal worsens.

The reason is voter turnout. Embarrassingly small in normal off-year elections, turnout this year is expected to reach record lows. And in part because of the Clinton controversies, disgusted Democrats are less likely to vote than upbeat Republicans. A survey conducted by the Republican Tarrance Group and the Democratic Lake Snell Perry & Associates shows that among those most likely to vote in congressional elections, Republicans lead Democrats by seven percentage points.

Fear is palpable among the Dems. One Democratic senator confides that all his colleagues would prefer to march down to the White House and ask the President to resign. But they won't because they know he'll refuse. So for now they're preparing for the worst. One Democrat who doesn't face reelection until 2002 contacted supporters recently to begin fundraising now. Congressman Charles Rangel (D-New York) told National Public Radio: "This is a presidential election, no matter how you cut it." Most of his fellow Democrats sincerely wish it weren't.

--Jeffrey H. Birnbaum