Trouble for centrists: Is the Hill headed for a sharper split?

Connecticut's junior senator wasn't the only congressional moderate named Joe to lose his primary election last week. Rep. Joe Schwarz (R) of Michigan also went down in a stiff challenge from within his own party – in this case, from the right.

And now another moderate senator – Lincoln Chafee (R) of Rhode Island – is fighting for his political life. If he survives the well-funded challenge of a conservative in his Sept. 12 primary, he faces another tough fight in the general election.

In an election year marked by strong anti-incumbent feeling and the potential for significant Republican losses, many of Congress's moderates – those willing to buck their party leadership at times – are vulnerable. In the House, the potential loss of Republican moderates could intensify the chamber's partisan polarization, adding to the challenges of George W. Bush's final two years as president.

"If Democrats defeat moderate Republicans, it will have the mirror effect of 1994, where you had Republicans defeating moderate Democrats," says Gary Jacobson, a political scientist at the University of California, San Diego. "That boosts polarization, no question."

The long-developing trend toward homogeneous congressional districts – those where partisan preference in presidential elections matches the partisan preference for member of Congress – may become even more pronounced with the vote Nov. 7.

Regional "purity" could also be enhanced. Just as the Southern Democrat has become nearly extinct, so, too, could the "Rockefeller Republican," named for Nelson Rockefeller, former governor of New York and a liberal Republican. The Northeast, home to one-third of the most vulnerable House Republicans, could lose many longtime members.

And in the Senate, the epitome of the Rockefeller Republican, Senator Chafee, is facing a tough primary challenge from Stephen Laffey, the conservative mayor of Cranston, R.I. Mr. Laffey is backed by the antitax, anti-"pork" Club for Growth, a Washington-based group that spent more than $1 million in helping to defeat the moderate Congressman Schwarz last Tuesday. But the Chafee-Laffey race is Club for Growth's marquee contest this cycle. So far, the group's members have sent $600,000 to Laffey, and its political action committee is running ads against Chafee.

If Laffey wins the nomination, polls show the Democratic candidate, former state Attorney General Sheldon Whitehouse, beating him soundly. In a blue state where a plurality of voters are independent and only 12 percent are registered Republicans, Chafee would seem to represent the Republicans' best shot at keeping that seat. A Rasmussen Reports poll released last week showed Mr. Whitehouse beating Chafee in the general election, 44 percent to 38 percent.

To the Club for Growth, there's nothing to lose in knocking off the incumbent. "Chafee and Whitehouse are alike on economic issues, so there's not much downside," says David Keating, the group's executive director. "The upside with Laffey is large. He could be a transforming figure in Rhode Island and provide a strong outsider voice in Washington."

To people who care about which party controls the Senate – and a Democratic takeover of that chamber is not impossible – Chafee's seat is crucial. And to Republican moderates working hard to protect their own, the argument to Republican primary voters in Rhode Island for nominating Chafee is obvious.

"It's a fact in Rhode Island that if Linc Chafee is defeated in the primary, the Democrats will pick up that seat," says Sarah Chamberlain Resnick, executive director of the moderate Republican Main Street Partnership.

It may be Chafee's ironic misfortune that he is up for reelection in a year when Democrats and independents are showing increasing impatience with Republican control of Capitol Hill. In Rhode Island, he is more popular among Democrats than among Republicans – he is the only Republican senator to vote against going to war in Iraq and he did not vote to reelect Presi-dent Bush in 2004 – but he could end up losing in November, if nominated, just because he has an "R" after his name.

"This is a year when the Democratic base is really ticked off," says Darrell West, a political scientist at Brown University in Providence, R.I. "Democrats really want Democrats representing them."

Ultimately, the future of "centrism" in the Senate is not in as much peril as it is in the House. Even if Sens. Chafee and Joseph Lieberman (now running in Connecticut as an independent) lose their seats, there will be plenty of moderates remaining, such as Republicans Olympia Snowe and Susan Collins of Maine, and Democrats Mary Landrieu of Louisiana and Ken Salazar of Colorado.

The club could even gain some new members come January. Bob Casey of Pennsylvania, a moderate Democrat known for his opposition to abortion rights, continues to poll ahead of his opponent, Rick Santorum, the No. 3 Republican in the Senate. In Tennessee, Democratic Congressman Harold Ford Jr., a centrist activist in the House, is in a tight race to replace retiring Sen. Bill Frist (R).

Professor Jacobson at UCSD, an expert on political polarization, also sees how new voices of moderation would enter the scene if Democrats take over the House. To win a majority, Democrats will have to win some Republican-leaning districts, and those members will have to take some moderate positions to keep those seats.

Also, having a Republican president and probably a Republican Senate could have a moderating effect on a newly Democratic House.

But there's a counter scenario: If the Democrats do retake the House, after 12 years in the wilderness, they may be tempted to behave as the Republicans did after taking over in 1994 – showing little interest in compromising with the minority.

"They could overplay their hand by being too partisan," says Thomas Mann of the Brookings Institution, a think tank in Washington. "They could go back on the promises they made about running the House and, in two years, be back in the minority."