Donald Trump didn't spar any words when it came to his thoughts on Ted Cruz choosing Carly Fiorina as his running mate, even as the Texas lawmaker's campaign is stalling.
"Cruz can't win, what's he doing picking vice presidents?" Trump said.
Trump is now the only candidate with a shot of clinching the nomination ahead of this summer's Republican convention, but Cruz is trying to force a contested convention.
Trump told a rally crowd in Indianapolis on Wednesday night that Cruz "is the first presidential candidate in the history of this country who's mathematically eliminated from becoming president" but nonetheless named a running mate.
Indiana will vote Tuesday.
"If we win Indiana, it's over," Trump said.
Trump now has 80 percent of the delegates he needs for the Republican nomination, though he could still fall short and have to battle Cruz for the nomination at a contested convention. Trump must win 48 percent of the remaining delegates to avoid that scenario.
Cruz's White House hopes now rest largely in Indiana. That's where he announced that he was tapping Fiorina as his vice presidential pick, bringing aboard a prominent Republican woman who has been eager to take on both Trump and Democratic front-runner Hillary Clinton.
In fiery remarks, Fiorina panned Trump and Clinton as a pair of liberals who would do little to shake up Washington.
"They're not going to challenge the system — they are the system," Fiorina said.
Cruz hoped that adding Fiorina to his potential ticket would be a draw for Republicans desperate to keep Clinton out of the White House. Fiorina, the former Hewlett-Packard chief executive, was frequently praised for her tough criticism of Clinton during her own presidential campaign and also irritated Trump with her sharp retorts during GOP debates.
Since dropping out, she has become Cruz's most active surrogate, making frequent campaign appearances alongside him and on her own.
Candidates typically wait until they've secured their party's nomination before picking a running mate, in part to avoid appearing to be getting ahead of the will of the voters.
But in Cruz's case, the announcement seemed aimed at keeping up the idea that he has a claim to the nomination and potentially attracting more voters in Indiana and other remaining states — including Fiorina's home state of California.
Trump won more than 50 percent of the Republican votes in Pennsylvania, Connecticut and Maryland in Tuesday's elections, and scored over 60 percent in Delaware and Rhode Island.
While Cruz grasped for a way to slow Trump, the businessman turned his attention to the general election. In a wide-ranging, though often vague, foreign policy speech, Trump sought to answer questions about his temperament and preparedness to be commander in chief.
He outlined a doctrine that he said would put American interests first and leave allies to fend for themselves if they don't contribute financially to back up security agreements. He vowed to send U.S. troops into combat only as a last resort, a break from years of hawkish Republican foreign policy.
"Our goal is peace and prosperity, not war and destruction," he declared in a 38-minute address that was heavy on broad statements and light on specific policy details. Unlike his rambunctious, free-wheeling rallies, the event featured Trump reading prepared remarks in a measured tone off a teleprompter.
Based on reporting by The Associated Press.