Republican White House hopeful Mitt Romney dodged mounting speculation Monday about a potential running mate, even with Senator Marco Rubio, the man now in the VP spotlight, standing right beside him.

Rubio is the latest among potential vice presidential picks to hit the campaign trail with Romney, but the first since the frontrunner’s main rival Rick Santorum bowed out of the Republican race two weeks ago.

Romney has already pivoted toward President Barack Obama ahead of the November election, telling supporters at a town hall event in Aston, Pennsylvania about the president’s “great failings” and saying it was time to “take back America.”

He was more reserved about who might be his deputy in that quest.