Coming Up on 'This Week': Rep. Paul Ryan and Rep. Chris Van Hollen

WASHINGTON, MARCH 30, 2012— -- Rep. Paul Ryan, R-WI., and Rep. Chris Van Hollen, D-MD., square off on health care, the budget, and the 2012 presidential race, Sunday on "This Week with George Stephanopoulos."

More Republicans line up behind presidential front-runner Mitt Romney, and Washington braces for an election-year budget showdown, as House Republicans pass their budget blueprint this week. Fresh off his endorsement of Romney, House budget committee chairman Rep. Paul Ryan, squares off against the top Democrat on the budget committee, Rep. Chris Van Hollen on their drastically differing budget and tax priorities and on the 2012 presidential election.

And President Obama's signature health care law goes on trial, as the Supreme Court hears arguments on whether "Obamacare" will remain the law of the land. How will the high court's decision impact the president's signature legislative achievement, and what will it mean for his chances for a second term? Ryan and Van Hollen go head-to-head, Sunday on "This Week."

Then, our powerhouse roundtable weighs in on all the week's politics, from the Supreme Court to the campaign trail, with George Will, conservative commentator Ann Coulter, former White House environmental advisor Van Jones, author of "Rebuild the Dream," Matt Bai of The New York Times Magazine, and "Nightline" co-anchor Terry Moran.

Will the Supreme Court's health care ruling change the political landscape? As more Republicans coalesce around Mitt Romney and Rick Santorum slips in key polls in upcoming primary states, how long will the fight for the nomination continue? And does Newt Gingrich's latest staff shake-up signal his campaign is at the end of the line? Plus, Mega Millions mania sweeps the nation – did the roundtable catch lotto fever?

See the whole political picture, Sunday on "This Week."