The other day, a couple of students asked me about the likelihood of a"six-year itch" for the Repubs in 2006. With the occupation of Iraq growing increasingly unpopular yet no signs existing that it will end soon, and as increasing deficits at least raise the possibility of an economic downturn, the Republicans would seem vulnerable. In the last five sixth-year midterm elections (1958, 1966, 1974, 1986, and 1998), only in 1998 did the out-of-power party not score well. And 1998 was clearly a historical anomaly: the Repubs had already made record gains in 1994 House races, and the reaction to impeachment hurt the GOP.

On the surface, the closest parallel to 2006 seems to be 1966--one party in control of all branches of government, and the party in power forced to confront some of the ramifications of policy choices made earlier in the decade. The GOP gained nearly 30 House seats in 1966 and scored some big-name Senate wins as well--Chuck Percy in Illinois, Robert Griffin in Michigan, Edward Brooke in Massachusetts--by running against LBJ's conduct of the war and targeting a theme of"law and order."

For a variety of reasons, though, 2006 seems unlikely to become a Democratic version of 1966. First, of course, redistricting has made House races all but non-competitive nationwide. An extremely talented Democrat--say, newly elected congresswoman Melissa Bean--can oust an extremely vulnerable GOP incumbent such as Phil Crane, but there's little reason to believe that there will be many more competitive House races in 2006 than the handful that were truly in play last year.

That leaves the Senate. Unfortunately for the Dems, 2000 was a first-rate Dem year in Senate elections, and so the weaker Republicans (such as former senators Slade Gorton of Washington, Spencer Abraham of Michigan, and Bill Roth of Delaware) were ousted six years ago. On paper, the most vulnerable Republican incumbent for 2006 is Rick Santorum, who seems far too conservative for his state, but Dems last won a regularly scheduled Pennsylvania Senate race in 1962. Arizona's Jon Kyl also seems like a possible target, as a 1994 freshman who got a pass in 2000 and who represents a state where Dems have fared a bit better lately. But Dems last won an Arizona Senate seat in 1988, and talk that John Kerry might be competitive in Arizona last year proved unfounded. Missouri's Jim Talent could be vulnerable, given his narrow margin of victory in a 2002 special election. On the other side, Nebraska Dem Ben Nelson seems highly vulnerable, given that he barely won in 2000 against a weak GOP challenger.

In the end, as was the case in 2004, the most likely changeovers will occur in open seats. Bill First (TN) and Trent Lott (MS) are expected to retire, but no one thinks the Dems will win a Mississippi Senate race, and the Tennessee Dems still haven't recovered from 1994, when the party lost both of the Volunteer State's Senate seats. The Montana seat held by Conrad Burns is more promising--like Ben Nighthorse Campbell in 2004, Burns seems like the kind of candidate who could announce a late retirement, and there have already been rumors, which he has denied, that the 70yo incumbent might step aside. On the other side, however, this week's Roll Call reported that New Mexico Dem Jeff Bingaman, one of the upper chamber's lowest-profile members, is considering retirement, which would likely yield a wild wide-open race in which all three of the state's House members might run. In Maryland, meanwhile, five-term incumbent Paul Sarbanes is mulling retirement, and a recent poll showed a divided Democratic electorate with the possibility of a racially polarizing promary between Baltimore mayor Martin O'Malley and former NAACP head Kweisi Mfume--this in a state where Repubs won the governorship in 2002 and performed more strongly than expected for much of the 2004 presidential race.

And then there's the case of Robert Byrd, who, from all outward signs, is planning on standing for a ninth term in 2006. Byrd has never been seriously challenged. But WV has drifted considerably to the right in the last eight years. Byrd certainly can't be considered safe.

Political conditions, obviously, can change a lot in 22 months. But as things stand now, it's hard to see a major shift, one way or the other, in midterm Senate elections.

Update, 7.33pm: NCEC is out with its Senate races to watch; it too sees tough sledding ahead for the Dems, especially Minnesota's Mark Dayton. (Dayton is the senator who shut down his Capitol Hill office a couple of weeks before Election Day.) It lists RI as a Dem possibility, but only if Lincoln Chafee loses a primary, which I don't foresee.