First openly LGBT person to be elected to the US Senate

Tammy Baldwin's official Congressional portrait

Last night (6 November 2012), Tammy Baldwin became the first openly LGBT person to be elected to the US Senate, representing Wisconsin. She is also Wisconsin's first woman Senator.

http://en.wikipedia.org/wiki/Tammy_Baldwin
http://www.tammybaldwin.com/
http://www.guardian.co.uk/world/2012/nov/07/wisconsin-senate-results-tammy-baldwin

You can see her victory speech here:
http://www.towleroad.com/2012/11/tammyspeech.html
 
UPDATED 3 January 2013
Tammy Baldwin was sworn in to the Senate, becoming the  first openly gay US Senator
http://www.huffingtonpost.com/2013/01/03/tammy-baldwin-senate_n_2404459.html

Interestingly, her successor in the Wisconsin State Congress, Mark Pocan is also openly gay. Another first, apparently.
http://en.wikipedia.org/wiki/Mark_Pocan
http://www.gaystarnews.com/article/openly-gay-candidate-mark-pocan-wins-tammy-baldwins-us-house-seat071112