For the fifth election cycle in a row, there will be more Republican than Democratic open seats. This time, the reason is clear. Being in the minority in the House is no fun, especially compared to the alternative. And it’s a vicious cycle. The more that Republicans retire, the more certain it is that the House will remain in Democratic hands.

As of today, 17 Republicans and five Democrats have announced their intentions not to run for their seats in 2008. Surely we will see a few more. But the majority of additional retirements will be of two types. First, there will be some last-minute decisions based on sudden scandal or health or other personal reasons. Second, there may be members who are holding their retirement announcements until just before the filing deadline so that they can give a leg up to their son, daughter or political protégé.

For Democrats, five open seats is a historically low number. Assuming there are no additional retirements, it would be their lowest total in over 80 years. Seventeen Republican open seats is on the higher side. Since 1960, their high-water mark is 24 open seats.

But more significant than the number of open seats are the reasons that members are leaving and the number of competitive seats that could change hands.

On the Democratic side, three of the five are running for Senate (the two Udalls, Mark of Colorado and Tom of New Mexico, as well as Maine’s Tom Allen), and Julia Carson (Ind.) is retiring for health reasons. For most members, the question is: Why retire now, when you are back in the majority? The staff of the Democratic Congressional Campaign Committee isn’t spending a lot of its time on retaining current members. Its members want to stay.

Moreover, all five Democratic open seats are safe. John Kerry won these districts with a minimum of a 9 percentage-point margin. The only one Republicans could reasonably point to as an outside chance is Tom Udall’s seat, which Bush lost by 9 percentage points. But by a quirk of fate, all three New Mexico representatives are leaving the House to run for the Senate, and Udall’s 1st district seems the least likely to change hands.

The Republican side is full of people looking to leave. Only the two New Mexicans, Heather Wilson and Steve Pearce, are running for Senate. The others have decided for one reason or another that their time to leave has come. And the list includes a remarkable number of influential people, including icons of the House like Ray LaHood (Ill.), leadership figures like Deborah Pryce (Ohio), committee ranking members Jim McCrery (La.), Duncan Hunter (Calif.) and Jim Saxton (N.J.), and appropriations cardinals like David Hobson (Ohio) and Ralph Regula (Ohio).

Republicans will also have to defend a large number of open seats that are in competitive districts. Eight of the 17 sit in districts that Bush won by 8 percentage points or less. They are (in order of lowest Bush vote to highest), Wilson, Pryce, Saxton, Mike Ferguson (N.J.), Jerry Weller (Ill.), Rick Renzi (Ariz.) and Regula. These eight races, along with a couple of scandal-plagued seats, like John Doolittle’s (Calif.), and a few incumbents like Robin Hayes (N.C.) and Dave Reichert (Wash.), who survived scares in 2006, round out the Democrats’ top target list.

Republicans also should hope that members in tough districts, like Mike Castle (Del.), Tom Davis (Va.) and Bill Young (Fla.) don’t enjoy their Christmas break so much that they return with retirement on their minds.

Republicans lost nine open seats in 2006. The current landscape does not look as dire, but four or five seems like the right ballpark.

Fortier is a research fellow at the American Enterprise Institute.