There are a few freshman Democratic congresspeople who were narrowly elected in 2008 on the backs of either unusually high black turnout or student turnout, or both. Mary Jo Kilroy (Ohio State University) and Tom Perriello (University of Virginia) clearly snuck into office with the help of students. Bobby Bright of Alabama got a big boost in black turnout. If these congresspeople face equally strong challengers, they are highly vulnerable to defeat in 2010, as Stu Rothenberg notes. This isn’t because of any votes they’ve taken or any constituents they’ve failed to serve. It’s simply a feature of lower voter interest in midterm elections. As a general matter, Democrats benefit from higher interest and higher turnout. This feature of American politics is showing up in the Virginia governor’s race, where the Democratic nominee Creigh Deeds is trailing in most polls by double digits, almost entirely based on the pollsters’ estimates of differential enthusiasm between the Republican and Democratic bases. Democrats’ responses indicate a much lower likelihood than Republicans’ that they will actually turn out to vote.

But, of course, turnout models aren’t the only thing that will be different in 2010. There is a reason that incumbents are rarely defeated. Sitting politicians have a variety of advantages over their challengers. A Democratic congressperson can make inroads with the farmers and ranchers in their districts by winning a seat on the Agriculture Committee, for example. They can win funding for important projects in their districts. They have two years in office to win over some of the people who supported their opponents in the last election. And, in most cases, they will have a money advantage over their challengers. The Democrats who snuck into office on the back of high black and student turnout will not lose simply because there are less of those votes available next time. They’ll lose if they can’t use their advantages to compensate.

Or, as sometimes happens, the national mood of the country will turn against either the Democratic Party or incumbents more generally. The Republicans are operating in a confusing political milieu. On the one hand, their base got very riled up in August and the GOP saw a major uptick in both large and small fundraising, and in candidate recruitment. A small window opened, Obama’s poll numbers plummeted, and the GOP took advantage. However, polling numbers of the Republican Party and their leaders is really in the toilet, and Obama’s numbers have rebounded. The GOP felt rewarded by letting the crazy loose, which has only encouraged them to keep the crazy going. And, it appears that they’ve unleashed a monster they can’t really control. Some of their best recruits are now being pressed by truly unhinged primary challengers.

Fundraising and candidate recruitment are the two best indicators of how a national federal election is going to go. From that standpoint, the GOP is looking pretty good. But, while I am concerned, I am cautiously optimistic that the strengths of August will turn out to be weaknesses come November 2010.