Coming Up on This Week with George Stephanopoulos

— -- This Sunday, George goes "On the Trail" with former Sen. Fred Thompson, R-Tenn. This week, the former "Law and Order" star received a major endorsement from National Right to Life. How will the endorsement help Thompson's campaign? George joins Thompson in Florida to hear about his race for the White House as we close in on the first contests of 2008.

Then, on our "Roundtable," David Brooks, Donna Brazile, Jake Tapper and George Will debate the week's politics.

And our "Voice," Kayce Freed Jennings on the legacy of ABC News' Peter Jennings and the new biography, "Peter Jennings: A Reporter's Life."