He has been President Donald Trump's loyal soldier in the fight against the Russia investigation — but it could cost him bigly in the midterm elections.

Republican Rep. Devin Nunes won his House of Representatives seat for the 22nd District in California by a whopping 35 points in 2016. But now, as the 2018 election approaches, the election is much more precarious than it should be, as NPR's Tim Mak reported.

Mak notes that recent polls put the race much closer than his previous win, with one recent survey finding his opponent below by only 5 points. While it still seems quite likely that Nunes will win, this will definitely be one race to watch if Democrats have an unexpectedly big win in November and there's any sign of a systematic polling error underplaying the party's chances. Compared to 2016, Nunes will be much more nervous on election night than he might have expected.

Nunes can thank his unblinking support of Trump. As chairman of the House Intelligence Committee, Nunes led the much derided and prematurely closed investigation in the chamber of Russia's interference in the 2016 election and potential collusion with the Trump campaign. The California Republican made it clear from the start that he intended to shield Trump from scrutiny and deflect blame on to others, which has led to his absurd crusades against the Obama administration, Deputy Attorney Rod Rosenstein, and others within the Justice Department.

As Mak noted, the nationalization of local races can hurt Nunes. Though he's become a hero for Trump fans, his prominence as the president's champion in the House hardly endears him to his district.

Mak reports:

"He's made a decision he can pretty much do what he wants and ignore local concerns...if he just nationalizes this whole race," said Liz Mair, a Republican who runs the Swamp Accountability Project and is opposing Nunes as part of her organization's effort to protect Mueller's Russia investigation.

California grows half of the fruits, nuts and vegetables eaten in America, most of it grown in the state's Central Valley. In the district, constituents care deeply about agriculture, immigration and water — but Nunes has spent much of this past term in the House focused on criticizing Mueller and blocking additional investigations into President Trump's potential ties to Russia

This has won Nunes a "Defender of Freedom" award from the American Conservative Union, a national organization. But the Mueller investigation isn't an issue that resonates locally among Nunes' supporters or detractors.

"The Russia issue is relevant insofar as it takes away the political capital that he has now in Washington to focus on what people care about here," said Janz, who says he's the one who can give local representation to the district. "I think that this race is about taking back the Central Valley."

Mak also notes that Nunes has done little to make himself available to local constituents, accentuating his image problems. His campaign didn't even an interview request from NPR — a sign of his disregard for voters.

He has certainly maintained some support in his district, which is why all the polls still show him with a lead in the race. But his antics have made a once-safe seat a newfound vulnerability — and Nunes can't be happy about that.