ASTON, Pa. - Mitt Romney declined to endorse Sen. Marco Rubio's version of the Dream Act today, saying that though it has "many features to commend it" he is still studying the immigration proposal.

"He and I have spoken about his thinking on his version of a different act than the Dream Act that's been proposed in the Senate," said Romney, standing next to Rubio for his first press availability in more than a month.

"The one that's been proposed in the Senate creates a new category of citizenship for certain individuals," said Romney. "The senator's proposal does not create that new category but instead provides visas for those that came into the country as young people with their families."

"I'm taking a look at his proposal," said Romney. "It has many features to commend it. But it's something that we're studying."

Pressed on his own immigration plan, and whether there is any group of undocumented people in the U.S. who he would consider giving some sort of legal path to citizenship to other than members of the military, Romney said he would be speaking about this "down the road."

"You know, I anticipate before the November election, we'll be laying out a whole series of policies relating to immigration," said Romney. "And obviously our first priority is to secure the border."

"I've spoken about the need to have a visa system that's right-sized for the needs of our employment community," said Romney. "How we adjust the visa program to meet the needs of the country is something I'll speak to down the road, but I don't have anything for you on that."

Romney brushed aside questions about whether he would consider Rubio, a first-term senator, as sufficiently qualified to be his running mate.

"I don't think I have any comments on qualifications for individuals to serve in various positions in government at this stage," said Romney. "That is something that we're going to be considering down the road as we consider various potential vice presidential nominees."

Rubio, who barely spoke during the joint press conference other than a brief introductory statement, did chime in at this point.

"I'm not talking about that process anymore," said Rubio, smiling, seemingly gun shy after accidentally referring to himself as the vice president during an interview last week.