(CNN) - On Thursday, Newt Gingrich reacted to one of the most coveted political endorsements of this presidential cycle: Florida Republican Sen. Marco Rubio's backing of Mitt Romney.
"It makes sense," Gingrich told CNN during a flight to Wisconsin. The former House speaker is set to campaign in Milwaukee later Thursday and has scheduled events in the Badger state both Friday and Saturday.
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"He's a very bright guy and I have great respect for his judgment," Gingrich continued regarding Rubio.
"We'll see what happens next Tuesday," the candidate continued, referencing Wisconsin's upcoming primary.
Gingrich has frequently praised the first-term senator, a rising star in conservative circles. In January, at the CNN Florida Republican presidential debate in Jacksonville, the former House speaker was asked which Hispanic leaders he'd appoint to a Gingrich cabinet.
"I actually thought about Marco Rubio on a slightly more dignified and central role, then being in the cabinet, but that's another conversation," Gingrich said.
Yet in his endorsement of Romney, Rubio essentially closed the door on the notion of a Gingrich primary win.
"The primary's over by the admission of the candidates who have admitted that they can't win the primary," the Florida senator told CNN National Political Correspondent Jim Acosta Thursday.
"They said the only way they can win is at a floor fight in Tampa. And I think that a floor fight in Tampa would be the worst possible thing we could do in terms of winning in November. So I think Mitt Romney, by the admission of his opponents, has won the primary and it's time for us to get behind our nominee," Rubio said.
Asked if Rubio is correct – that the GOP race is essentially over – Gingrich responded:
"It's over when Romney gets to 1,144," Gingrich said, referring to the number of delegates needed to win the Republican presidential nomination. "And he hasn't gotten there yet."
Gingrich also addressed harsh comments from one of his top financial supporters. Despite he and his family fueling Gingrich's candidacy to the tune of over $15 million through a supportive super PAC, billionaire Las Vegas businessman Sheldon Adelson recently said Gingrich is "at the end of his line."
"No comment," the former House speaker said.