Gage Skidmore

I laughed when I saw Politico’s headline: Indiana mystery man upends bloody GOP Senate primary. That’s a reference to businessman Mike Braun, who looks like he might actually beat out conservative U.S. Reps. Luke Messer and Todd Rokita and earn the right to take on vulnerable Democratic incumbent Sen. Joe Donnelly in November. The contest has been bruising and personal, but it’s also notable for the strategies that have been employed. All three of the candidates believe that they’re engaged in a contest to convince Indiana Republican voters that they’ll be a better friend to the president than the alternatives.

Each of the three Republicans has tried to claim the Trump mantle. Braun, doubling down on the outsider message, says in his closing argument TV ad that he’s running “because President Trump paved the way.” In one of his television spots, Rokita dons a Make America Great Again hat. Messer’s office said last week he is “actively gathering support” in Congress to nominate Trump for next year’s Nobel Peace Prize for bringing North Korea and South Korea to the negotiating table to end the Korean War.

This is related to another issue. As far back as April 8, the New York Times was reporting that many Republican strategists think the best way to mobilize conservative voters for the midterms is to use the prospect of impeachment (if the Republicans lose control of either chamber of Congress) as a motivator. By the end of April, this idea had cemented itself into common wisdom.

The degree to which Trump maintains support with the Republican base has been exaggerated but he’s definitely more popular with them than Congress. On the other hand, there’s an old saying that everyone hates Congress but most people like their own representatives. And this is certainly backed up by the consistent success rate of most incumbents running for reelection.

There’s a tension in the impeachment strategy because it isn’t broadly applicable. Most vulnerable Republicans are running for office in districts where the president’s approval numbers are under water. We’ve already seen the Democrats win some state and federal elections in districts that voted heavily for Trump in 2016. That indicates that a lot of Trump voters have already abandoned him or at least are not willing to transfer their allegiance to him to other Republicans.

The impeachment strategy is aimed at the latter group. It’s a way of saying “you may not like me, but you need me to protect the president.” It makes sense in a Republican primary, but I think it’s a much less effective strategy in a general election. The degree to which it can be effective at all depends on the characteristics of the district, but it’s premised on the idea that the Republican candidate can win if only he can get all the Trump voters to turn out for an election in which Trump is not on the ballot.

The first problem is that they’ll never achieve that level of turnout. The second problem is that Trump’s base isn’t as big as it was. Looking, for example, at the recent Monmouth College poll of Obama-Trump voters in key Midwestern districts, I see about a 20 to 25 percent drop-off in support for the president.

The poll surveyed Obama-Trump voters — persons who voted for President Obama in 2012 and then President Trump in 2016 — in three battleground Midwestern congressional districts: Iowa’s 1st Congressional District, located in the northeastern part of the state and with a Republican incumbent; Wisconsin’s 3rd Congressional District, located in the southwestern part of the state and with a Democratic incumbent; Minnesota’s 8th Congressional District, located in the Iron Range northeastern part of the state and with an open seat. In the three districts polled, strong majorities of voters say they will definitely or probably vote for the president in 2020 (Iowa-1: 63%; Wisconsin-3: 61%; Minnesota-8: 68%). The shares of those who said they will definitely or probably not vote for Trump ranges from 21-25%.

That’s a significant loss of support and it can’t be made up by raising the prospect of Trump’s impeachment. It’s probably worse than that, too, because while it’s impressive that Trump is still holding on to more than 60 percent of his voters who cast a ballot for Barack Obama, they’re the least reliable voters in his coalition and the least likely to have a strong preference for a more traditionally Republican candidate. It’s unlikely that a GOP candidate for Congress will get all of their votes no matter how much they cuddle up to the president.

It’s also almost a given that Trump’s problems will become more pronounced between now and the election and that more people will see impeachment as an appropriate remedy for his presidency. Being on the record as being implacably opposed to accountability in the Russia matter may become much more of a vulnerability than an asset.

The impeachment strategy therefore makes some sense in the short-term if you’re trying to win a primary for Senate in Indiana. But it’s not a good or safe strategy for blunting the Democrats’ enthusiasm advantage in the fall.