Sen. Marco Rubio speaks at CPAC, March 14 2013.
U.S. Senator Marco Rubio is weighing in on North Korea's attempt to use an open letter to begin dialogue with South Korea.
Rubio is wrapping up his trip to Asia with a stop in South Korea. He met with US troops and South Korean government officials.
Rubio still urges caution when it comes to dealing with North Korea.
"There's an expression in America that talk is cheap," says Rubio. "It needs to be followed up by something that begins to create confidence - on the part of the South, but also on the part of the whole world - that they're serious about changing the destiny of the direction that they're heading."
Rubio also visited Japan and the Philippines.