(CNN) - Sen. John McCain, the 2008 Republican presidential nominee, had high praise on Sunday for House Budget Committee Chairman Paul Ryan, who was introduced Saturday as GOP presidential candidate Mitt Romney's running mate.
"Excellent choice. A new generation of leadership in our party and in our nation," McCain said on Fox News. "A man who understands the most compelling challenges this nation faces obviously are jobs and the economy."
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"I am convinced that he will bring the kinds of ideas and thoughts that he's been pursuing in the House and a very important position that he's held," McCain continued, echoing praise he offered in a Saturday paper statement - that "Ryan has proven that he is fully prepared to address our nation's economic challenges."
Ryan, who for seven terms has represented a Wisconsin district in the U.S. House, rose to head the influential Budget Committee in 2011 and is known for his ideas both innovative and controversial to rein in spending, especially on Medicare.
McCain said Ryan's Capitol Hill experience is an asset to Romney, who has made a selling point of his status as a Washington outsider.
"I think it's a good matchup because of Paul Ryan's ability to carry a Romney agenda through the Congress of the United States," McCain said.
With the economy and budget issues in the forefront this year, "There's nobody that knows these issues better than Paul Ryan," he added.
And his comparative lack of private sector experience - a contrast to Romney - contrasts sharply with President Barack Obama, McCain said.
"Someone would have to tell me what experience President Obama has in the private sector, which he has amply shown he is abysmally ignorant of, but Paul Ryan brings the balance of understanding of how the Congress works, understanding how the budget process works," he said in the interview.
Democratic National Committee chairwoman Debbie Wasserman Schultz, who followed McCain on Fox News, characterized Ryan and his budget - including the Medicare proposal - as "extreme" and said Romney has "fully embraced" Ryan's proposal.
Kevin Madden, a spokesman for Romney's campaign, characterized Romney's relationship with the Ryan budget plan differently when speaking to reporters.
Asked how the plan fits into Romney's own campaign, Madden answered, "Governor Romney is at the top of the ticket, and Governor Romney's vision for the country is something that Congressman Ryan supports."
Romney talking points obtained by CNN after the Ryan introduction on Saturday said Romney "applauds Paul Ryan for going in the right direction with his budget, and as president he will be putting together his own plan for cutting the deficit and putting the budget on a path to balance."
McCain, who is known in part for his military experience and foreign policy chops, said that Romney's foreign policy experience is "the least probably since Ronald Reagan," but that he "understands our nation's challenges."
Asked in the interview if the selection of Ryan presented a "danger that the running mate may overshadow the actual candidate on some of the most important issues of the day," McCain - who selected Sarah Palin to join his ticket in 2008 - chuckled through his answer.
"I had that problem," he laughed, then turned more serious and continued, "No, I don't think that's the case."
"There obviously is very good chemistry between the two of them and Americans recognize that running mates are very important, but it's the top of the ticket obviously that makes what the voters decide on as they enter the ballot booth," he said.
– CNN's Peter Hamby and Rachel Streitfeld contributed to this report