Ted Cruz. Reuters/Charles Mostoller Sen. Ted Cruz suspended his presidential campaign on Tuesday following a crushing primary loss in Indiana to Donald Trump.

In his concession speech on Tuesday night, Cruz made no mention of Trump, but told supporters that he no longer saw a clear path to secure the nomination.

"Tonight, I'm sorry to say, it appears that path has been foreclosed," Cruz told supporters.

"We left it all on the field, Indiana, we gave it everything we've got. But the voters chose another path," he added.

Cruz's decision to exit the race essentially guarantees that Trump will secure the necessary number of delegates needed to clinch the Republican presidential nomination on the first ballot at the Republican National Convention in July. Ohio Gov. John Kasich said that he would remain in the race, but so far has won only his home state as well as a handful of delegates in other nominating contests.

The senator campaigned vigorously in Indiana, where he hoped that more favorable demographics would help the him win a chunk of delegates.

Cruz announced his potential vice-presidential running mate, former Hewlett-Packard CEO Carly Fiorina, in Indiana last week. He also made numerous retail stops, greeting supporters at five locations on Monday alone while his wife, Heidi Cruz, appeared at five separate stops without him.

But as the primary neared, polls showed Trump pulling far ahead in the Hoosier State.

The real-estate magnate unleashed his trademark harsh rhetoric in the final days against Cruz, whom he accused of being "crazy."

"Ted does not have the temperament to be doing this," Trump said at a rally on Monday. "He's choking like a dog because he's losing so badly. We've got to put him away tomorrow, folks."

Trump was more gracious in victory Tuesday night. During a victory speech at Trump Tower, he called Cruz "one hell of a competitor" who has an "amazing future."