Once Al Franken officially becomes a member of the Senate next week, Senate Democrats will hold a powerful majority. But even with 60 votes in its caucus and the ability to override filibusters, the Democratic Senate majority is hardly in a position to ignore the opposition.
"This could prove to be very important. It takes 60 votes to bring the debate to a close and get a vote on a bill," said Steven Smith, a political science professor at Washington University in St. Louis. "By having that 60th senator, the Democrats can do with one fewer Republican, make fewer concessions to Republicans -- or to a handful of Republicans -- in order to overcome a filibuster and get a bill passed. So it's potentially very important."
In recent years Senate minorities of both parties have blocked legislation even though the legislation has majority support, by refusing to vote to cut off debate.
Earlier this year, Democrats' hopes of reaching 60 became a possibility when Sen. Arlen Specter of Pennsylvania left the Republican Party to become a Democrat.
At the time, Sen. John Cornyn, the head of the National Republican Senatorial Committee, wrote that if Franken won and Senate Democrats reached 60, "Republicans will have lost the ability to meaningfully impact legislation in any way."
Jennifer Duffy of the Cook Political Report says while 60 is a magic number when comes to Senate rules, it's not as consequential as it's sometimes presented.
"I've always believed this whole notion of 60 votes was something of an arbitrary number, because on any given vote, both parties lose a couple of members," she said. "Even since Sen. Specter switched to the Democratic Party, his voting record has not changed all that much. In fact, the first two votes he cast as a Democrat, he sided with Republicans."
But Former Vice President Walter Mondale says getting to 60 could be enough to break some logjams.
"The Senate has been tied up with one filibuster after another," he said. "This gives a chance to get a little more momentum in the Senate."
Smith says Democratic leaders still must compromise with centrists in their caucus on controversial issues, from health care reform to global warming. But he says the party leadership will be in a stronger position to round up Democratic votes to cut off debate.
"There will be more pressure on those centrist Democrats to stick with the party, when the party has the numbers within its own caucus to close debate and get a vote on a matter," Smith said.
"So Franken's presence, I think, will intensify some of the pressure on those other Democrats," Smith continued. "Of course, it also makes them all that much more pivotal, and they'll be using their bargaining leverage with their own leadership to extract concessions on key legislation."