INDIANAPOLIS — Republican Ted Cruz faces a high-stakes test for his slumping presidential campaign in Tuesday’s Indiana primary, one of the last opportunities for the Texas senator to halt Donald Trump’s stunning march toward the GOP nomination.

Cruz has spent the past week camped out in Indiana, securing the support of the state’s governor and announcing retired technology executive Carly Fiorina as his running mate. Yet his aides were pessimistic heading into Tuesday’s voting and were prepared for Cruz to fall short, though the senator vowed to stay in the race, regardless of the results.

“I am in for the distance, as long as we have a viable path to victory,” Cruz told reporters on Monday during a campaign stop.

Trump devoted more time to campaigning in Indiana than he has to most other states, underscoring his eagerness to put his Republican rival away and shift his attention toward Democratic front-runner Hillary Clinton. While Trump cannot clinch the nomination with a big win in Indiana, his path would get easier and he would have more room for error in the campaign’s final contests.

“Indiana is very important, because if I win that’s the end of it. It would be over,” Trump said during a lunch stop Monday in Indianapolis.

Republican leaders spent months dismissing Trump as little more than an entertainer who would fade once voting started. But Republican primary voters have stuck with the billionaire businessman, handing him victories in every region of the country, including a string of six straight wins on the East Coast.

Clinton and Vermont Sen. Bernie Sanders also faced off in Indiana’s Democratic primary on Tuesday, though the stakes were lower than in the Republican race. Clinton holds a commanding lead over Sanders — she’s secured 91 percent of the delegates she needs to win the nomination. That means she can still win the nomination even if she loses every remaining contest.