One sleepless night I saw this infomercial for Tony Robbins, where a
testimonial was delivered by a guy who said he used to be in some sort
of street gang (I believe it was the Black Panthers), and was now a
senator. I sent emails to Robbins'company, but they're not helping,
so...
 
Who is this guy?

Hello,

You must be thinking of Bobby Rush, a former Black Panther who is now
a congressman from Illinois. See his biography at
(http://www.house.gov/rush/bio.htm).

It's obvious that there are no former Black Panthers in the U.S.
Senate, since there are no black people in the U.S. Senate.

I hope this answer meets your needs. If not, please request
clarification.

Search strategy:

black panther politician
://www.google.com/search?sourceid=navclient&q=black+panther+politician

Bobby Rush
://www.google.com/search?sourceid=navclient&q=Bobby+Rush

This is the second time I've had to post this question, which gives
you an idea of how hard it was. Well done!