In the modern political era, the Democrats assume they will need 60 votes to pass anything, based on their fear of a Republican filibuster. Personally I would like to see this theory tested in practice a little more often, just so the general public gets a clear sense of exactly who is obstructing legislation, but I will concede that the current Democratic majority in the Senate is so razor thin as to make that a moot point.
The majority will be significantly larger in the new Congress, but still not up to 60, barring a surprise in Georgia and a recount victory for Al Franken in Minnesota. What this means is that Obama's chances for success, on anything will hinge on being able to convince two or three Republicans to cross party lines. Everything. A new stimulus plan, health care, climate change -- the works. For at least two years, the power to steer the U.S. economy is going to be controlled not by the President who gained 63 million votes, not by the majority party in both the Senate and the House, but by that rarest of nearly extinct creatures, the moderate Senate Republican.
Maine, with its two moderate Republican Senators, is about to become the most important state in the union.
Step one is re-framing the filibuster as a somewhat extraordinary act and not the intentional design of American democracy. Actually making the Republicans execute the filibuster would help.