EXCLUSIVE: George Stephanopoulos Interviews Presidential Hopeful John McCain

Tuesday night at the GOP candidates' debate he solidified his position as one of the frontrunners for the Republican nomination, and Sunday morning John McCain sits down with George Stephanopoulos, On the Trail in Iowa.

Sen. John McCain, R-Ariz., the like Republican nominee, had tough words for Sens. Barack Obama, D-Ill., and Hillary Clinton, D-N.Y., saying their anti-NAFTA stance may have a ripple effect in support for global anti-terror efforts.

The Arizona Republican has been face to face with voters in town hall meetings around the country, and this week George joins him for an event in Pella, Iowa.

McCain has been one of the most prominent supporters of the bipartisan, but controversial, Senate immigration legislation. As a vote on the bill nears, he'll talk to George about what's at stake in the battle to secure the border.

McCain has also been under fire for his position on the Iraq war – a position consistently at odds with the majority of the American people.

Then on the roundtable, ABC News consultant Torie Clarke, Time Magazine's Jay Carney, and ABC's Claire Shipman and George Will join George to debate the week's politics.

All that plus Voices and Funnies coming up on THIS WEEK.