With at last an initial bipartisan deal on the budget, we now have definitive proof that both of the parties have *not* been equally responsible for the inability to get bipartisan agreement on any budget deals.
Of course there was overwhelming evidence before this: Mitch McConnell's statement that his top priority was to defeat Obama—and not to govern; the unprecedented and largely successful effort by the Republican minority in the Senate to block all legislation supported by the Democrats through the filibuster; and the repeated passing of bills by the Republican House that had no chance of passing the Senate.
But now we have definitive proof. Another key method of the obstructionism has been the Republican House leadership refusing to bring up votes without a majority of their own caucus in favor. It has been this deeply anti-majoritarian policy, along with the flagrant abuse of the filibuster in the Senate, which have been responsible for this being the least productive congress in history.
The definitive proof is that in the last hours of this congress, Boehner finally allowed a bipartisan vote, without a majority of his party. And we got a compromise bill. If the Republicans, with their hatred of government, had not been blocking majorities, against the explicit wishes of the American founding fathers, we wouldn't have had the blockage.
Update Jan 3: According to this story what occasioned Speaker of the House Boehner telling Senate Majority Leader in the White House to "go fuck yourself," and repeating it and being unrepentant in his rudeness was exactly that Reid had called him on his preventing majority votes, calling him a 'dictator.' In fact, Boehner had no civil reply because his previous policy—the so-called 'Hastert rule'—is anti-democratic and explicitly against the principles of the founding fathers. Hence the f-bomb. Further evidence that this incident has laid bare the anti-democratic obstructionism of the Republicans.