Marco Rubio walks a fine line on Donald Trump

Marco Rubio and Donald Trump at a GOP debate. (Photo: Jim Young/Reuters)

Florida Sen. Marco Rubio offered lukewarm support for Donald Trump on Tuesday, while reiterating that he doesn’t want to be his running mate in November.

Rubio, a former top-tier presidential candidate, said during a CNN interview that he would fall behind the presumptive GOP nominee because he had signed a pledge to do so.

“I intend to support the Republican nominee,” Rubio said.

Rubio was once one of Trump’s fiercest critics. Before he withdrew from the race last March, Rubio repeatedly attacked the real estate magnate as a “con man,” among many other jabs.

“Friends don’t let friends vote for con artists,” he said at one point.

Rubio ultimately pulled the plug on his campaign. Trump became the presumptive nominee last week after his last two primary foes suspended their White House bids.

At least two of Trump’s other former GOP rivals — former Florida Gov. Jeb Bush and South Carolina Sen. Lindsey Graham — have since said they could not bring themselves to vote for either Trump or Hillary Clinton, the Democratic frontrunner.

During his CNN interview Tuesday, Rubio said he stood by his past attacks against Trump. But he repeatedly stressed that he would not be taking similar shots at him during the general election.

See the graphic: Where the Republican Party stands on Trump >>>

“My differences with Donald — both my reservations about his campaign and my policy differences with him — are well-documented and they remain,” Rubio said when asked about potentially becoming Trump’s vice president.

“He would be best served by having people close to him in his campaign that are enthusiastic about the things he stands for,” he added.