Getting a bill on the Senate Floor is often much harder than passing it.  That’s because the Senate operates on Unanimous Consent agreements (UC’s, as they are called) – meaning that any time, any Senator can block a piece of legislation from coming to the floor.  With Senate floor time closely guarded, it appears that the Patent Reform Bill might just fall victim to a tight floor schedule and continued squabbling between key senators.  As of Thursday, April 10 – negotiations between Senators Hatch, Leahy and Specter seem to have collapsed.  Thus effectively killing the bill for the year.  This is by no means the end, but as time goes on, it will be harder and harder to the Senate to fit this bill into its already busy schedule. 

http://money.cnn.com/news/newsfeeds/articles/djf500/200804111432DOWJONESDJONLINE000870_FORTUNE5.htm