Next step for body scanners could be trains, boats, metro

From TheHill.com:

The next step in tightened security could be on U.S. public transportation, trains and boats.

Homeland Security Secretary Janet Napolitano says terrorists will continue to look for U.S. vulnerabilities, making tighter security standards necessary.

“[Terrorists] are going to continue to probe the system and try to find a way through,” Napolitano said in an interview that aired Monday night on 'Charlie Rose.'

“I think the tighter we get on aviation, we have to also be thinking now about going on to mass transit or to trains or maritime. So, what do we need to be doing to strengthen our protections there?”

Will there be a Fourth Amendment left at the end of all of this?