why does a member of congress vote as he or she does? like their race, gender, all that stuff.

Question

and where does the true power of congress lie?

Answer 1

http://www.google.com/search?q=congress+members+vote&rls=com.microsoft:en-us:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7SUNA

There are many articles and websites in the results above that will give you information. Congress includes both the House of Representatives and the Senate, so you're referring to over 530 people. Why these legislators vote as they do is not a simple question. Be sure to read several of these articles to get a sense of what happens.