From this Washington Post article:

Some Democrats wonder privately whether the measure will ever get that far.
Senate Majority Leader Harry Reid (D-Nev.) and Sen. Charles Schumer (D-N.Y.) released a letter this week offering reassurance to wary House Democrats that the bill has a chance of becoming law.
But while Reid and Schumer committed “to working tirelessly for Senate consideration of the House-passed bill,” they offered no firm promise that the measure would ever hit the floor of their chamber. The Senate version has 50 co-sponsors and it’s not clear whether the 60 votes necessary to overcome a certain GOP filibuster could be mustered.
Even if the bill does get to Obama’s desk, it could face legal hurdles.
“I think the chances that it would be challenged [in court] would be 100 percent,” said Rick Hasen, a professor at Loyola Law School in Los Angeles and the author of the Election Law Blog, adding that the bill’s opponents would likely seek a preliminary injunction to bar it from going into effect. …