Sen. John McCain on Syria: "Instead of a red line, we gave him a green light"

Pressure is mounting on the Assad regime, after the latest reports of a deadly chemical attack. Opposition groups say it killed more than 1,300 people. President Obama says the U.S. is still gathering information about what happened, but acknowledged, "this is clearly a big event of grave concern." It is raising serious questions about how his administration will respond. John King spoke with Senator John McCain who says the President has already "lost credibility" on ending the crisis in Syria.