Midterm turnout surges for both parties

A surge in voter enthusiasm has prompted millions more Democrats to cast ballots in primary elections this year, a turnout explosion ahead of midterms in which motivation to vote is key to the party's chances of reclaiming control of the House.

However, Republican voters also are showing up in higher numbers than in previous midterm cycles, a sign that the GOP's fate will be sealed not by apathetic conservatives who sit out Election Day, but by voters open to persuasion from both parties.

The Hill's analysis of primary elections held in 30 states so far, through Tuesday night's contests, shows voters in both parties are turning out in higher numbers than in either of the last two midterm elections.

Almost 13.8 million people have voted in Democratic primary contests this year — 5 million more than the 8.7 million who had voted in the same states in the 2014 midterm elections, according to data maintained by state elections offices.

On the other side, 12.3 million people have picked up a Republican ballot so far this year — 2 million more people than the 10.3 million who had cast ballots in a GOP primary in the same 30 states four years ago.