Former Sen. Rick Santorum (R-Pa.) is throwing his support behind controversial presumptive Republican presidential nominee Donald Trump. "I'm 100 percent," Santorum said Tuesday during an interview on Fox News's "On The Record," when asked if he was supporting or endorsing Trump. "That's endorse." Santorum, who backed Marco Rubio after dropping out of the race himself in February, said he spoke with Trump more than a week ago and he said the businessman asked for his support.