Stephen Colbert's congressional appearance on behalf of immigrant farmworker exploitation

A Colbert segment from 2010 in which Colbert appears as an "expert witness" at the invitation of Rep. Zoe Lofgren (D-CA) to testify before Congress.  Colbert stays in character the whole time until the very end, which is not on this clip when a Representative asks him why he is wasting their time.  Colbert responds something to the effect, "These people are vulnerable and do back breaking work.  If I can use my celebrity to call attention to their plight, I'm doing it."

[youtube http://www.youtube.com/watch?v=k1T75jBYeCs?feature=oembed]