WASHINGTON (AP) — Rick Santorum says Sen. John McCain, who spent 5 1/2 years enduring brutal treatment in a North Vietnamese prison, doesn't understand how effective waterboarding and other harsh interrogation techniques can be.The Republican presidential contender made the comments in a radio interview Tuesday with Hugh Hewitt.Last week, McCain said in a Senate speech that waterboarding and other severe interrogation tactics did not provide the information that led to al-Qaida leader Osama bin Laden's compound in Pakistan. He said his information came directly from CIA Director Leon Panetta, and the head of the Senate intelligence committee backed up the assessment.Santorum insisted that the tactics led to bin Laden.A spokeswoman for McCain said she wouldn't dignify the comments with a response.