Shifting Picture

The fight for control of the House is getting more ink than the battle for control of the Senate, but several recent shifts in individual Senate races merit attention.

All year, talk about the Democrats' chances of taking the Senate has focused on the five most endangered Republican incumbents.

They are, roughly in order of vulnerability, Rick Santorum of Pennsylvania, Conrad Burns of Montana, Lincoln Chafee of Rhode Island, Mike DeWine of Ohio, and Jim Talent of Missouri. The discussions then turn to the second tier of vulnerable Republicans, speculating whether Democrats can perhaps pick up a sixth seat (the most likely prospect is the open seat in Tennessee that Majority Leader Bill Frist is vacating) and whether they will be able to hold on to all of their own Senate seats.

The open seat in Minnesota and Maria Cantwell's seat in Washington state are the Democrats' biggest vulnerabilities.

According to this line of thinking, Senate seats elsewhere are unlikely to change party -- even though Democrats are fielding strong challengers to Arizona's Jon Kyl and Virginia's George Allen, and even though the races for the Democratic open seat in Maryland, the independent open seat in Vermont, and the seats of Democratic incumbents Debbie Stabenow of Michigan, Ben Nelson of Nebraska, Robert Byrd of West Virginia, and Robert Menendez of New Jersey are theoretically competitive.

But that overall picture is changing a bit. The Arizona race between Kyl and wealthy real estate developer Jim Pederson has become as competitive as the Tennessee contest. In other words, for Democrats to gain the six Senate seats they need to seize control (provided they can hold all of their own turf), they must beat all of the Big Five vulnerable Republicans, plus win in either Arizona or Tennessee.

But Cantwell is beginning to look more vulnerable than she'd been expected to be. Holding her seat may be more difficult for Democrats than holding their open seat in Minnesota, where Rep. Mark Kennedy is carrying the GOP banner and Hennepin County (Minneapolis) Attorney Amy Klobuchar is the Democratic nominee.

Although a few other Senate contests feature credible challengers, these nine races (seven of them for seats now held by the GOP) are the most likely to produce party switches. And the bulk of the action, money, and attention will be focused there.

Inside the Beltway, the open Democratic seat in Maryland, where Paul Sarbanes is retiring, is getting considerable attention. Republicans have an even-money shot at holding that state's governorship, but the Senate race is a more difficult proposition. Maryland remains a very Democratic state. Gov. Robert Ehrlich is the first Republican since 1980 to win any statewide office, and many observers say his victory was mainly due to the extraordinary weakness of the 2002 Democratic nominee.

Across the river in Virginia, Democrats are touting their newly minted nominee, James Webb, who was secretary of the Navy during the Reagan administration. He appears unlikely to defeat Allen, but he is benefiting from the state's changing demographics. Virginia is becoming less reliably Republican as its northern suburbs continue to grow. At the very least, this contest is a nuisance for Allen, because it keeps him off the presidential campaign trail.

Perhaps the most important thing to remember about Senate races is the domino effect. In cycle after cycle, the closest Senate races all tend to break in one direction on Election Day. By the end of the 1998 campaign season, The Cook Political Report listed seven races as toss-ups; Democrats went on to win six of them (86 percent).

Going into the 2000 election, we rated nine as toss-ups; Democrats won seven (78 percent). Two years later, Republicans won six of nine toss-up races (67 percent). And in 2004, Republicans won eight of nine (89 percent).

With at least two-thirds of the toss-up contests breaking in the same direction even in "non-wave" elections, even a relatively small number of competitive races can have a big effect on the makeup of the Senate. So, Republicans shouldn't take much comfort from the fact that only nine states appear likely to produce truly competitive contests this year.