Mission possible?

A former secret agent is unnerving Donald Trump during his final push in an ever-tightening race for the most public job in the world.

The most recent average of polls at RealClearPolitics shows independent presidential candidate Evan McMullin surging in Utah. The former CIA agent is running 6 points behind Trump and slightly ahead of Democrat Hillary Clinton.

It’s enough to get under Trump’s skin. Over the weekend, the Republican nominee complained about the conservative McMullin in an interview with Fox News. “The guy is taking votes away from me,” Trump said. “He’s a puppet of a loser.”

If McMullin wins Utah, it would be the first time a third-party candidate won a state in a presidential contest since 1968, when American Independent Party candidate George Wallace carried a bloc of five Southern states.

But McMullin is contemplating an even bigger “if” scenario: If he wins Utah, and neither Trump nor Clinton receive the 270 electoral votes needed to prevail in the Electoral College, the newly elected House of Representatives—likely to be controlled by Republicans—would determine the next president. The House would choose from the three candidates with the most electoral votes.

This scenario is extremely unlikely and would hinge on Trump prevailing in nearly every battleground state. But with the latest Clinton email revelations upending the contest in a forceful October surprise, both front-runners need every electoral vote they can muster.

Even Trump acknowledged McMullin’s spoiler potential in the Fox interview. “Now for some reason, if we lose Utah, that could have a very devastating effect on the overall,” Trump said. “If they go enough for this character that’s running all over the state, and we lose the state of Utah, that’s devastating.”

McMullin has made character a central theme in his campaign. After Trump’s interview, McMullin jabbed the GOP candidate by tweeting, “Yes, you’ve never heard of me because while you were harassing women at beauty pageants, I was fighting terrorists abroad.” And followed up with: “We will not sit by while two corrupt, self-serving, big-government liberals like you and Clinton destroy our country.”

McMullin’s background fighting terrorists with the CIA during the post-9/11 years is largely classified, but the station chief who supervised him overseas told The Washington Post McMullin excelled at developing intelligence contacts under dangerous conditions: “People fundamentally trust Evan.”

The socially conservative Mormon is a popular candidate in Utah, the state with the largest Mormon population in the country, and McMullin has acknowledged his candidacy is as much about sending a message as winning the race.

“I believe no matter what happens on Nov. 8, if we can send a strong message here from Utah … it will change the discussion in Washington,” he told a crowd in mid-October.

Meanwhile, another conservative candidate, Darrell Castle, continues to make a case for voting third party. Castle, the Constitution Party candidate, said in a phone interview from his Memphis law office he didn’t agree with the notion that voting for a third-party candidate was throwing away a vote.

“If you’re voting for what you think is right, how can you be throwing your vote away?” said Castle, who isn’t close to winning a state.

The pro-life evangelical and fiscal conservative said he understood why some voters felt bound to use their votes to block the opposing candidate, and he acknowledged, “I clearly see what they are trying to prevent.”

But Castle also appealed to Christian voters to consider the character of the person they choose: “My understanding of Scripture is the Bible tells us quite clearly what type of leaders we should look for to hold public office. And I’d invite people to search their minds and see if they can find anyone like that.”