Republican Gov. Bob McDonnell of Virginia and Democratic Gov. Martin O'Malley of Maryland, normally allies on regional issues, on Sunday squared off for the first time as the leaders of their national parties' efforts to win state elections next year.

McDonnell, chairman of the Republican Governors Association, said reining in government spending is the key to economic prosperity. O'Malley, chairman of the Democratic Governors Association, pushed for greater spending on education and infrastructure, saying the government had to do more as unemployment hovers stubbornly above 9 percent.

While generally cordial during their joint appearance on CNN's "State of the Union" show, O'Malley and McDonnell offered a preview of the polar-opposite positions they will take as they preside over the gubernatorial-election hopes of their parties heading into 2012.

"Martin and I get along great," McDonnell said. "He's a great Irish-American. [But] we've tried stimulus spending. He continues to try to blame Bush."

O'Malley, meanwhile, lambasted congressional Republicans for their resistance to compromise during negotiations over raising the nation's $14.3 trillion debt ceiling, nearly forcing the government to default on its financial obligations.

"A modern economy requires investment," O'Malley said. "That debacle of driving our country to the brink of default is not helpful to consumer confidence or investment confidence."

For the first time, rating agency Standard & Poor's downgraded the U.S. credit rating from AAA to AA+, citing, among other deficiencies, the toxic political environment in Washington.

O'Malley took the helm of the Democratic Governors Association, which will aid the party's gubernatorial candidates in 2012, in December. McDonnell took the lead with Republican governors just last week when the group's previous chairman, Texas Gov. Rick Perry, stepped down from the job to run for president.

Both governors have been mentioned as possible vice presidential candidates or for administration posts if their party wins the White House.

O'Malley repeatedly echoed President Obama's demand that any deficit-reduction plan must be balanced between spending cuts and new tax revenues. Obama's attempt to push tax increases during debt negotiations was rebuffed by Republicans at every turn.

O'Malley told CNN that the deficit was "driven, fueled and caused primarily by Bush-era tax cuts," while McDonnell countered that it was "crushing mandates," particularly health care and environmental regulations, that exacerbated a steady flow of red ink in many states.

While holding the chairman's post, O'Malley has consistently attacked the Tea Party and, in particular, Rep. Eric Cantor, R-Va., for obstructionist tactics -- claims that McDonnell dismissed on Sunday.

"Words like 'dinosaur wing' and 'extremists' are not helpful to civility in our country," he said in a not-so-veiled jab at his rival governor across the Potomac.

Both McDonnell and O'Malley enjoy widespread popularity and easily won their respective elections. Now both will spend the next few months cultivating a national profile as they oversee fundraising, networking and the direction of their parties' efforts nationwide.