WASHINGTON -- A leading House Republican said Tuesday he hasn't had a discussion with Republican presidential front-runner Mitt Romney about taking the No. 2 spot on the ticket this fall.

Wisconsin's Congressman Paul Ryan said the subject hasn't come up, but said he enjoys working with the former Massachusetts governor, whom he has endorsed.

But on the matter of joining Romney on the ticket, Ryan told NBC's "Today" show that he hasn't "given enough thought to that question."

"I think he still has to go through the process of nailing it down. He still has opponents," Ryan said.

He suggested that Romney is miscast politically because he served as governor of Massachusetts, a state with a liberal tradition, saying, "he reminds me of a sort of earnest, upper Midwest person." Ryan said that Romney "has the principles, the skills, the skills" to govern the country and put the economy on a stronger footing.

Ryan dismissed Obama's criticism of his budget plan. "You know, we’ve gotten kind of used to this sort of verbal tantrums from the president. To me it’s a little more petulance than presidential," he said.

In a separate interview on MSNBC, Ryan, chairman of the House Budget Committee, accused President Barack Obama of "putting us on the path to a debt crisis."

Ryan said the budget House Republicans are proposing would spare people 55 and over from cuts in programs like Medicare.

"The question is, do we reform these benefit programs ... or do we kick the can down the road," the Wisconsin Republican added.

Ryan dismissed Obama's Buffett Rule, which would make millionaires not pay a lower tax rate than middle-class earners, as "pixie dust." The president is pushing the plan Tuesday in Florida.

He also declined to define "rich." "I don't even want to get into what the cutoff is, because I don't think we should get into this definition." He added, "I'm not going to give you what I think is a rich person and what's not a rich person, because you have to look at the fact that these are job creators."