Former Pennsylvania Sen. Rick Santorum is running for president, he announced this morning. And unlike many of his other rivals, who tiptoe around the controversial Republican plan to scrap Medicare while praising author Rep. Paul Ryan (R-WI), Santorum jumped in this morning by calling himself tougher than Ryan when it comes to making hard choices about spending.

"I didn't back down on trying to reform the Social Security system," Santorum said when asked by ABC's George Stephanopoulos about his 2006 race, which he lost in a landslide. "In an election year, I went out to the floor of the United States Senate with Jim DeMint and started arguing for reforming Social Security."