President Barack Obama is "probably the most threatened president ever," says the ranking Republican on the House Homeland Security Committee.

Rep. Pete King (R-NY) told NBC's Matt Lauer that he supported the idea that Tareq and Michaele Salahi -- the socialite couple who gate-crashed a White House state dinner last week -- should be prosecuted as a "deterrent" to others who might want to try something similar.

"We can't show this type of weakness to terrorists, or to psychopaths, especially with President Obama, who is probably the most threatened president in our history," King said.

"That's why we have to have a full investigation to find out exactly what the Secret Service is doing to prevent this from ever happening again. First of all, how it happened, why it happened and how it will never happen again. And it put's us on notice. Yes, we do need more protection. We have to have more fall-back. If one Secret Service agent makes a mistake -- you have to assume someone's always going to make a mistake -- there has to be the backup. There has to be layers of defense," said King.

Ronald Kessler, author of In The President's Secret Service, told NBC's Today Show that the Secret Service has a recent history of security lapses.

"Bush White House aides would pressure [the Secret Service] to let people in at events and sometimes they would put people through magnetometers [metal detectors] but they would turn them off so that even if there was a weapon no alarm would sound," Kessler said. "I know that sounds unbelievable but that's what was going on."

Kessler told CBS last week that the Secret Service has been "cutting corners" since it was moved into the Department of Homeland Security in 2003, and the agency needs a management overhaul.

"The belief [inside the Secret Service] is that it's just a matter of time before there is an assassination," Kessler told Lauer. "The Secret Service has been shockingly derelict in its duty."

This video is from NBC's Today Show, broadcast Nov. 30, 2009.

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