Conventional wisdom says that Kevin Cramer leads Heidi Heitkamp in the U.S. Senate race in North Dakota. That might be right, based on the fundamentals, but that doesn’t mean he’s going to win. The U.S. Senate campaign in North Dakota is far from over.

The fundamentals are against Heitkamp, including partisan loyalty, voter turnout and previous results. Another of the fundamentals out of the candidates’ control might favor Heitkamp. That is timing.

This election occurs at the middle point of a presidential term when voters often punish the party of the sitting president. The downside for her is that voter turnout is less in midterm elections. In North Dakota since 2000, turnout in presidential years has never dropped below 60 percent while at midterm turnout has never been higher than 50 percent of eligible voters. This is important because higher turnouts tend to favor Democrats.

In 2012, Democrats had two reasons to show up. Heitkamp was one; the other was Barack Obama, running for re-election. Obama was popular in the state. He won 45 percent of votes in 2008 and 39 percent in 2012, the best back-to-back record for a Democrat since the Roosevelt landslides in 1932 and 1936.

Voters had turned against Obama in the 2010 midterm election, and the wave swept Democrat Earl Pomeroy out of the U.S. House, where he had served for 18 years. The winner was Rick Berg, identified closely with Republican leadership in the House.

The crucial issue in 2010 was health care. Pomeroy had voted for the Affordable Care Act, otherwise known as Obamacare. The wave receded in 2012, re-electing Obama and giving Heitkamp her narrow victory. This didn’t help Democrats farther down the ballot, however; Cramer was elected to the House, succeeding Berg, on the same day that Heitkamp won her Senate seat.

There’s something cyclical about this; these waves can be seen as corrections by voters in the aggregate — both those who turn out to vote and those who sit out the election. It amounts to a kind of buyers’ remorse.

Heitkamp has seized this to take control and gain momentum in this election cycle. Her campaign has emphasized the ACA’s provisions about pre-existing conditions, a vulnerability for Cramer, who joined the Republican effort to repeal and replace Obamacare — an effort derailed by the late Sen. John McCain’s vote against repeal. Heitkamp associated herself with McCain; her affectionate reminiscences were published in state newspapers. Heitkamp also has used newspaper advertising to re-enforce her position on pre-existing conditions, an effective way to reach older voters, a key part of her constituency.

Health care has replaced trade as the marque issue of the 2016 campaign. Cramer echoed the president’s line that tariffs now could lead to freer trade later, and that potential negative impacts are worth the risk. The issue is in a kind of suspended animation; it could emerge with consequential force, or it may fade away. He’s banking on the latter, and turned his own campaign to other issues.

To an unusual degree, these are national rather than strictly local issues. Cramer has aligned himself closely with Trump and his presidency. Trump’s percentage of the vote was the largest for any candidate since 1984, when Ronald Reagan was re-elected. In 1986, at the midterm election, Reagan campaigned for incumbent U.S. Sen. Mark Andrews, who lost. It’s impossible to assess the impact of Trump’s full-throated support of Cramer’s campaign, but the candidate himself seems to revel in it. Presidential campaign visits are rare in North Dakota; Trump has made two, and several sitting Cabinet members have visited the state.

Cramer’s campaign emphasizes his support of the president, including the vote pending in the Senate to confirm a presidential Supreme Court nominee. Heitkamp’s vote is potentially crucial; she supported an earlier Trump nominee. Interest groups opposing the pending confirmation have tried to provide cover for Heitkamp’s potential opposition by arguing that the nominee could provide a court majority to overturn critical parts of Obamacare. Heitkamp’s own advertising has criticized the state attorney general’s decision to join a lawsuit challenging the law.

For Heitkamp, this amounts to a double-edged sword. A vote to confirm probably won’t attract any additional votes to Heitkamp, because Trump’s most passionate supporters are committed to Cramer. Democrats could decide to stay home, however, and she needs their votes to win. The calculation becomes whether or not the confirmation vote would be a make-or-break issue with voters not already committed to Cramer, voters who might be feeling buyers’ remorse after Trump’s election.

Style matters here. Heitkamp’s campaign portrays her as a thoughtful person of independent judgment in contrast to Cramer’s near complete allegiance to the president.

This will play out during the 49 days remaining in the campaign; we’ll know the outcome at the end of Day 50, after the polls have closed and the votes are counted.