U.S. Sen. Rand Paul of Kentucky placed fifth in the Iowa Republican Caucuses on Monday, raising further questions about the viability of his presidential campaign and when he might divert his attention to defending his Senate seat in earnest.

Paul’s attention has been primarily focused on the presidential race, in which he has fallen from being “the most interesting man in politics,” as proclaimed last year by Time magazine, to sharing a tiny piece of the Republican electorate dominated by frontrunners Ted Cruz and Donald Trump.

Paul gained 4.5 percent of the vote in the Iowa Republican Caucuses. Cruz, a U.S. senator from Texas, won the Iowa caucuses ahead of businessman Donald Trump.

But Paul will face two Republican challengers in the May U.S. Senate primary election. More daunting is the General election, where he’ll likely square off against Democratic Lexington Mayor Jim Gray, a wealthy businessman.

Steve Voss, a political science professor at the University of Kentucky, said the pressure will continue to mount on Paul to prioritize his campaigning after the performance in Monday’s Iowa Republican Caucuses.

“Any candidate performing poorly in early nomination contests will face headwinds that hinder progress,” Voss said. “They struggle to access campaign cash, and insiders who previously supported them start looking for positions with competitive campaigns.”

Paul’s Senate campaign has a modest $1.4 million on hand, and Gray has shown that he’s willing to self-fund his political endeavors, having spent $800,000 on his first race for mayor.

Paul’s next presidential contest will be the New Hampshire Primary on Feb. 9, where he’s hovering around 3 percent in the polls.

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Voss said that despite the lackluster run for president, Paul still has name recognition with Kentucky voters, and he hasn’t had embarrassing episodes on the presidential campaign trail.

“In a contest with Trump and Cruz and (Ben) Carson it’s hard to get national attention,” Voss said. “Paul has managed to avoid any especially damaging gaffes during his presidential run, so on balance I do not see how he’s hurting himself back home.”

At Paul’s request, the Kentucky Republican Party opted to hold a presidential caucus this year instead of the traditional primary election, allowing him to simultaneously vie for the presidency and his Senate seat.

The caucus will be on March 5.

That may be a strong reason for Paul to stay in the race a little longer. Dewey Clayton, a political science professor at the University of Louisville, said Paul will feel pressure to not drop out before the Kentucky caucus.

“It would be a huge embarrassment for him to not make it to Kentucky’s caucus, given that Kentucky’s Republican Party change the rules specifically for Rand Paul so he could do this,” Clayton said.

But at the same time, Clayton said that Paul “no longer has the luxury of just totally ignoring the Senate race.”

“He’s had to come out and defend his voting record in the Senate and his time in the Senate from accusations that he’s too busy flying around raising money and campaigning for the presidency than looking after his job that he was elected to do by the citizens of Kentucky,” Clayton said.

The Paul campaign characterized his result in Monday’s Iowa Republican Caucuses as a “strong top-five finish,” noting that he placed ahead of candidates such as Jeb Bush and John Kasich.

“Tonight’s vote reveals that the race for the White House is wide open,” the Paul campaign said in a news release Monday night.

On Monday night, Paul tweeted that he would continue his presidential campaign after taking in 4.5 percent of Republican votes in the Iowa Republican Caucuses.

“We fight on! Thank you for all of your support,” Paul said.