Chris Christie: There's no evidence Trump was spied on

Christie, a former federal prosecutor, said it would be extremely difficult for the Obama administration to get clearance for that kind of surveillance and would require attorneys to go before a judge to obtain warrants.

“I know from having spent seven years as a U.S. attorney that the FISA court and the way that works and foreign intelligence surveillance activities – it is very, very difficult to get that type of activity going,” he said. “You have to go and convince an independent judge.”

“So I don’t see any evidence of that at this point in time. We’ll continue to listen, but I can tell you from my experience that kind of stuff is very difficult to get.”