The terms “wave” and “tsunami” are bandied about so often that it is easy to lose sight of the fact that there is no real definition for them. Everyone seems to agree that a “wave” election involves big gains for one party or the other. But what counts as “big”? This is complicated by the fact that most analysts agree that the GOP would not see large House gains this year even in a wave election, so we only have Senate races to analyze.

Sabato and Cohn both suggest that even GOP gains of seven Senate seats would not constitute a wave. Sabato has called a GOP gain of seven seats “Gale Force Whitecaps,” reserving “Tropical Storm Wave,” “Republican Tidal Wave,” and “Full GOP Tsunami” for gains of nine, 11, and 14 seats, respectively. Cohn writes “[t]he Republicans will still have a good chance of picking up the Senate without an anti-Democratic wave. There are so many Democratic-held seats up for grabs in red and purple states this year that the GOP could take the Senate under neutral conditions.” Brandon Finnigan likewise places the bar for the GOP at more than seven seats.

Without a firm definition of a “wave,” it is hard to engage the point. But I think the GOP knocking off three incumbents and picking up three open seats would typically be construed as a wave election. For what it is worth, I’ve held this view for quite some time: Last summer, when we were actually in a neutral environment, I gave the GOP around a 30 percent chance of taking back the Senate, assuming that things might break the GOP’s way. This February, my model — which I noted was probably too favorable to Republicans — suggested that a presidential approval rating of 50 percent resulted in the GOP picking up five Senate seats as the most probable outcome.