It is the ultimate Republican nightmare, the ultimate fantasy of Democratic spin. But with the 2000 campaign season already in full swing on Capitol Hill, the prospect of a Democratic takeover of Congress is starting to move beyond the realm of partisan pipe dreams.

"We're fixated on our survival right now," said John Feehery, a spokesman for House Speaker J. Dennis Hastert (R-Ill.). "Congress is definitely up for grabs."

The House certainly is, with Republicans clinging to a thin 10-vote majority, which would evaporate with the loss of five districts. And now that Rep. Rick Hill (R-Mont.) has announced his retirement and Rep. Bob Franks (R-N.J.) has decided to run for Senate, Democratic Congressional Campaign Committee Chairman Patrick J. Kennedy (R.I.) is crowing that so far, 14 of the 20 "open seats" for 2000 are being vacated by Republicans, the most favorable ratio for Democrats since their landslide in 1958.

Other House members may run for Senate as well, including Reps. Harold E. Ford Jr. (D-Tenn.), David Minge (D-Minn.), Frank LoBiondo (R-N.J.) and Bernard Sanders of Vermont, an independent who reliably votes Democratic. But the DCCC claims eight open seats now held by Republicans look competitive for 2000, versus three held by Democrats.

"That's the five-seat difference right there," DCCC spokesman Erik Smith said. "We're very excited about this. It seems like everything is coming together right now."

Polls suggest that the issues on the current congressional agenda--HMOs, campaign reform, gun control, Social Security, Medicare--tend to favor Democrats as well. But National Republican Congressional Committee spokeswoman Jill Schroeder says the GOP has an ace in the hole: the coattails of presidential favorite George W. Bush.

"The Democrats are running around measuring the drapes for their new offices, but it's way too early for that," Schroeder said. "The real thing to watch is the top of the ticket."

The Senate is supposed to be safer for Republicans, who hold a 10-vote cushion in the chamber. But 17 GOP incumbents are up for reelection, versus only 11 Democrats, with five open seats in play. Democratic Senatorial Campaign Committee political director Jim Jordan says he sees only one vulnerable Democratic incumbent, Sen. Charles S. Robb (Va.), versus as many as 11 beatable Republicans, notably freshmen Spencer Abraham (Mich.), Rod Grams (Minn.) and Rick Santorum (Pa.). With the decision by New Jersey Gov. Christine Todd Whitman (R) to forgo a Senate race, Democrats believe they have a legitimate shot at a coup.

In fact, even National Republican Senatorial Committee spokesman Stuart Roy acknowledges that for the most part, the GOP is playing defense in the Senate. "We don't want to lose seats, but for now, our goal is to just hold the majority," Roy said.

BUDGET GROUSING: It's one thing for Republican leaders to endure the taunts and hoots of Democrats as they engage in creative accounting to try to stay within tight budget rules this year. But it's quite another when fellow Republicans are the ones lobbing the grenades.

"Some senators complain and then some senators have to do something about it," Senate Majority Leader Trent Lott (R-Miss.) growled late last week following the latest blast from within his own ranks. "So what I need is less complaining and more action."

The majority leader was responding to open complaints from Republican Sens. Chuck Hagel (Neb.) and George V. Voinovich (Ohio) about the more blatant leadership efforts to circumvent the spending limits in passing appropriations bills.

"Most Americans do not understand budget terminology like 'forward funding' . . . 'advance funding' . . . '13 month fiscal years' . . . and other more creative terms and accounting methods," Hagel wrote in a letter to colleagues. "What the American people do understand are terms like 'smoke and mirrors' and 'dishonesty.' "

THE WEEK AHEAD: The House and the Senate will focus heavily on budget work this week. The Senate will also deal with a major bankruptcy bill, which Democrats hope to use as a vehicle to address a minimum wage increase and gun control measures. The House will vote on dairy regulations and health research legislation, and may take up the Senate joint resolution criticizing President Clinton's decision to grant clemency to members of a Puerto Rican terrorist group.

Staff writer Eric Pianin contributed to this report.