Ritter came to the attention of the Clinton Administration when he testified before Biden's committee. Remember, Biden was condescending and contemptuous to Ritter. Ritter made a few appearances pushing the "Saddam is dangerous" line, and then retired into obscurity.
However, he had come under the scrutiny of Mt. Doom, the Clintons. No doubt checking with their sources (remember at this time they still were in power) they discovered that Ritter was interested in underage girls. No doubt the Iraqis had photos, which they were happy to supply for a big price.
Ritter, the very public anti-Iraq critique, suddenly changes his mind. He appears on a bazillion talk shows spouting how President Bush should be impeached, that Cheney wants nothing but a war, that it's all for oil, approval ratings, or revenge for the attempt on Dad Bush's life.
Meanwhile, any evidence on Ritter has been suppressed. He doesn't know this, of course, but that is what is useful...he never knows when something may comeout. So Ritter goes on his merry way, trashing all things Bush at the behest of whoever has the dirt on him.
Whoever had the story quashed did so to keep him a viable critic of the administration's policy. Only two places would have an interest in Ritter performing that function: Baghdad and Chappaqua.