Warren Henry writes for the Federalist that Republicans should pay attention to election turnout numbers.

“It all comes down to turnout” is the hoariest truism in election coverage. We don’t yet know what it will be for the midterm election, but based on turnout for the primaries concluded in 2018, Republicans should be worried. The much talked of “blue wave” could very well be bearing down on the party.

In recent cycles, primary turnout has translated decently to the national vote for the House. The exceptions, 2004 and 2012, involved an incumbent president running for reelection. Midterms do not suffer from that problem (though individual state and district races may). Competitiveness will depend on how winnable politicians think elections may be.

The 2018 primary turnout numbers should alarm the GOP when compared with recent midterm “wave” elections. Before the 2006 blue wave, Democrats received 54 percent of 24.4 million primary votes. Before the 2010 red wave, Republicans won 56 percent of 28.5 million primary votes. In 2014, the GOP got 55 percent of a lower 23.9 million primary votes.

In 2018, even before the New York primary, Democrats won approximately 53 percent percent of an astounding 35.7 million primary votes. The Democrats have swung to a near 2006-level primary edge amid a 47 percent increase in overall turnout.