The 2018 Election Is Still Looking Good for House Democrats

In Defying the Odds, we discuss congressional elections as well as the presidential race.

Michael Malbin at Brookings:

Record numbers of Democrats continue to emerge who are willing to defy the normal odds by mounting early challenges to sitting House incumbents. As of June 30, we counted 209 Democratic challengers who had raised $5,000 or more. Three months later, the 209 had grown to 391 Democratic challengers with at least $5,000. Of these 391, 210 raised at least $50,000 and 145 raised at least $100,000. The following table shows the comparison across years with the columns showing the number of challengers who have raised at least the amount indicated. (A full set of data, including for each of the candidates, is available on the Campaign Finance Institute’s website.)
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What we really want to know, therefore, is not how many challengers are running, but how many incumbents are facing challengers. The following bar chart graphically shows the number of incumbents running against challengers who have raised at least $50,000.
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[M]any more Republican incumbents are facing Democratic challengers at this time of the year (at each funding level) than any other set of incumbents since 2003. Because multiple candidates are in fact running in some districts, the advantage is not quite as large as it was for the raw number of challengers. There were more than twice as many Democratic challengers in 2017 as Republicans in 2009. When we flip the question around, there are just short of one-and-a-half times as many Republican incumbents facing Democratic challengers in 2017 (at the various funding levels) as the other way around in 2009. While not as large an advantage as the raw number of challengers suggests, this is still considerable. The 2009 GOP cohort was larger than any other before this year. It was large enough to feed a major partisan shift in 2010—and larger than the Democrats need to become a majority in 2018.

Given the field of challengers, should we expect a Democratic wave in 2018 that could rival the 2010 wave for Republicans? These numbers tell us that Democrats are poised to take advantage of a wave if one develops. And based on past experience, a wave election would likely sweep out some incumbents who are not yet even challenged. But the challengers cannot make a wave election by themselves. That will depend upon the President’s performance, Congress’s performance, and the mood of the public. In other words, it is still the second inning. There are many more yet to be played.