One of the nation's top political analysts, Stuart Rothenberg, dissects politics at the congressional and statewide levels.

Senate overview

By Stuart Rothenberg/CNN

WASHINGTON (CNN) -- While the Republicans hold a 54-46 advantage in the U.S. Senate, 19 GOP seats and only 15 Democratic seats are up for election this year.

Both the total numbers and the number of senators up for re-election this year changed when Sen. Paul Coverdell, R-Georgia, died and former Georgia Gov. Zell Miller, a Democrat, was appointed to replace him. Miller is now up for election to fill the remainder of Coverdell's term.

The Democrats still have an outside chance to gain the five seats they need to control the Senate in 2001, but their chances have faded noticeably over the past few months. Connecticut Sen. Joe Lieberman's decision to run for re-election to the Senate at the same time that he is running for vice president is a huge impediment in the Democrats' efforts to re-take the Senate.

Of the 34 incumbents, five senators -- four Democrats and one Republican -- are not seeking re-election. Those retirements come close to mirroring the numbers in 1998, and mark the fifth straight election cycle when the retirement of Democratic senators have exceeded GOP retirements. A second Republican retirement was erased when Rhode Island Sen. John Chafee, who had announced his retirement at the end of his current term, died while in office. His seat was filled by his son, Lincoln, who is seeking re-election this year.

Only about half of the Senate seats up for election this year have serious competition. Four Democratic seats are now vulnerable, while about twice as many GOP-held seats are witnessing competitive races.

Democrats are in a better position because most of those seeking re-election are safe. Only Virginia's Chuck Robb is in trouble.

By contrast, six to eight sitting Republican senators face competitive races. A number of freshmen members of the class of 1994 appear particularly vulnerable, since they won in a great GOP year and have yet to prove themselves in a more neutral partisan political environment. That group includes Michigan's Spencer Abraham, Minnesota's Rod Grams, and Missouri's John Ashcroft. Pennsylvania's Rick Santorum also should be at risk, but Democratic challenger Ron Klink hasn't put together a good campaign, and Santorum looks likely to win easily. Poor Democratic recruiting in Ohio seems to have wasted an opportunity to threaten another 1994 GOP freshman, Sen. Mike DeWine.

Other GOP incumbents, including Slade Gorton in Washington, Montana's Conrad Burns, and William Roth in Delaware, face tough races. Chafee in Rhode Island looks surprisingly strong, though the state's Democratic bent creates some uncertainty.

The late announcement by Nebraska Sen. Bob Kerrey that he won't seek re-election was a setback for Democrats, since the state's partisan bent favors the GOP. But the Democrats have a good chance to hold the seat with the candidacy of former Gov. Ben Nelson. They also are favored to hold the open seat in New Jersey, where Sen. Frank Lautenberg is calling it quits.

However, a Democratic seat in Nevada, where Sen. Richard Bryan is retiring, looks highly vulnerable, and the open seat in New York, where Sen. Daniel Patrick Moynihan is calling it quits after 24 years in the Senate, is up for grabs. New Yorkers have not gotten the slugfest they once expected between first lady Hillary Clinton and Mayor Rudy Giuliani, but Long Island Rep. Rick Lazio has been a formidable Republican opponent for Clinton. In Florida, Rep. Connie Mack's retirement has given the Democrats a vulnerable open seat target.

In 1998, Democrats were on the defensive in Senate races. But instead of losing two or three seats, they broke even. That was a moral victory for them. This cycle, Republicans are in much the same situation and are hoping for a similar outcome.