A day after endorsing Mitt Romney, former Florida Gov. Jeb Bush told a Pennsylvania newspaper Thursday that his state's new senator, Marco Rubio, should be the running mate.

Bush, son and brother of the former presidents, told Selena Zito of the Pittsburgh Tribune-Review that Rubio, the young freshman senator elected in 2010, is dynamic, joyful, disciplined and principled.

He is the best orator of American politics today, a good family man. He is not only a consistent conservative, but he has managed to find a way to communicate a conservative message full of hope and optimism, Bush said.

Bush endorsed Mitt Romney for president after the ex-Massachusetts governor crushed Rick Santorum in the Illinois primary Tuesday night.

Romney Momentum Building?

The 59-year-old former Florida governor is yet another influential GOP name Romney can add to his list of endorsements. Bush is well-respected in his party and was rumored to have presidential ambitions of his own, but he put that speculation to rest last summer.

Rubio gained national popularity among Republicans in 2010 when he ran for the U.S. Senate and won in a three-way race. Republicans love the 40-year-old Cuban-American -- nicknamed the crown prince of the Tea Party -- not only for his conservative policy but his charm and picture-perfect family. Republicans began touting him as a potential future presidential candidate even before he joined the Senate. Like Bush, he is popular among Latinos in Florida.

The freshman senator hasn't endorsed a candidate yet and has told reporters he'll remain neutral until a nominee is chosen by the party.

Rubio's much-anticipated memoir, An American Son, is due for publication in October just ahead of the presidential election.