In today's Opinion Journal, Jay Cost makes a fascinating and highly persuasive case that the Republicans, despite their perceived political weaknesses, will hold on to their majorities in both the House and Senate this fall.
Cost bases his conclusion not on the policies or politics of the two parties but on history and the current configuration of the two legislative bodies. Cost notes that many pundits are predicting that the Republicans will hold on to the Senate but will lose their majority in the House. Among the important facts they are minimizing, however, are "2004's 98.8% incumbent retention rate or 2006's incredibly low 4.6% incumbent retirement rate" in the House. Even more persuasive, however, is Cost's analysis of trends in House and Senate turnover, and his explanation of why they are so.
I'll leave the full explanation to him, as it is very well don in his article, and will go right to his main point, which is that historically the House flips parties only when the Senate does. This is not a quirk but an ironclad rule of the entire past century (which is the relevant period because it includes the entire period during which Senators have been elected directly by popular vote rather than by the state legislatures).
As to whether this all simply means that the Senate will flip too, Cost points out the unlikelihood of that scenario:
Of course, one might respond, this argument could just as easily predict that both the House and the Senate will flip this year. The error that pundits are making, according to this line, is not with the House but with the Senate. Both are vulnerable. I do not find this compelling. One of the reasons pundits are so prone to write off the Senate is that they know more about the individual elections (this, by the way, is in keeping with senators' reduced incumbency advantage--individual senators are better known). They have a better sense of the electoral landscape, and therefore can appreciate that a net of six is prohibitively difficult. However, pundits know less of the specifics of House contests; thus, the House seems more promising. They cannot name the seats the GOP would have to lose to lose the House. If they could, they would find themselves naming many members most think are secure. A switch of the House still seems plausible, in other words, only because details are lacking.
History indicates that when the House switches, the Senate switches, too. Our knowledge of congressional elections implies that this is not coincidence. Accordingly, we can conclude that the safety of the GOP Senate strongly implies the safety of the GOP House. Further, we can issue a challenge to pundits who think the Democrats will take the House. They have an additional burden of proof: they must either indicate that the Senate will switch or why 2006 will be the first exception to a 92-year rule.
As Cost points out, even those most optimistic about potential Democrat gains in this fall's elections concede that the Senate is probably not going to flip. He notes that the concession that the Republicans will probably retain the Senate is probably correct, given that with less than 40 seats up for grabs and less than half of those being at all competititive this go-round, it's fairly easy to predict which ones will go which way and hence whether the Dems can make up their present deficit. The answer appears to be no, unless things change dramatically in the meantime.