Welcome back to The Sunday Grind, where we choose the most notable moments on the Sunday morning talk show circuit and serve them to you piping hot, with a side of biscotti. 

On This Week (minus George Stephanopoulos, who had the morning off), Jonathan Karl referenced The New York Times' front-page story on the possibility that the Republican presidential nomination will be decided on the GOP convention room floor, then asked guest Rick Santorum if he thought that was a possibility. Santorum said "there are plenty of delegates out there for us," and that voters are "tired of the negative ads" being put out by Romney. "[Romney] had a huge advantage," Santorum said, "and he hasn't been able to close the deal." He wouldn't answer Karl's question, however. Santorum did acknowledge regret over his support of party turncoat Arlen Specter when he made a pid for the presidency in 1996: "That certainly wasn’t one of my prouder moments that I look back on," Santorum said.

Back from a trip to southern Sudan, and an arrest protesting outside the Sudanese embassy in Washington, George Clooney appeared on the Sunday Grind circuit to press for action in the region. He told Meet the Press he can do more good as an actor on a talk show that he can actually running for office: "I think I actually have a lot more influence on it here. No super PAC has given me money ... There is no outside influence for me. I can actually have an opinion and it may not fit what the UN wants and it may not fit what other people want, and I can say this I think is right, and stand by it. I don’t have to check in to make sure and I don’t have to compromise.”

Clooney's message: Sudan's president Omar al-Bashir is blocking food and aid from reaching refugees hiding in the mountainous southern border of the country. He wants a joint diplomatic action by the U.S. and China, who import 6 percent of their oil from Sudan, to intervene and prevent a violent outbreak in the region.

John McCain marked his 64th appearance on Meet the Press today, surpassing Bob Dole's record, where he characterized Mitt Romney's performance as "improving," and points out that Super PACs have "played a key role unfortunately in my view, because most of them are negative ads and driven up the unfavorables of the candidates." He characterized the election as "the nastiest I've ever seen." McCain also said the contraception debate is hurting the party: "I think there is a perception out there because of the way this whole contraception issue played out – we need to get off of that issue in my view. I think we ought to respect the right of women to make choices in their lives and make that clear -- and get back onto what the American people really care about: jobs and the economy."

On Face the Nation, top Obama campaign adviser David Axelrod accused Republicans of making empty promises about reducing the cost of gas. He singled out Mitt Romney for having pledged to fire three cabinet officials charged with energy production -- Energy Secretary David Chu, Environmental Protection Agency head Lisa Jackson, and Interior Secretary Ken Salazar -- and accused Romney of lying:  "Mr. Romney will pander, and the poor American consumer will be left in the same position. So we need to keep going forward with an 'all of the above' strategy on energy." Highlight: Schieffer's "gotcha" moment, when he played conflicting clips of the president both mocking his opponents for promising lower gas prices, and then making the same promises on the 2008 campaign trail. Very Daily Show of you, Mr. Schieffer.