If you're wondering whether President Obama's ambitious second-term agenda has a chance to make it through Congress, that might be worth keeping in mind.

Here's an impressive fact about life in today's Washington: The last time a major new piece of policy legislation passed the U.S. Senate was July 15, 2010.

That's when the Dodd-Frank financial-reform bill came through the Senate. And it was 951 days ago.

If you're wondering whether President Obama's ambitious second-term agenda has a chance to make it through Congress, this little fact might be worth keeping in mind. Pessimistic analyses of the prospects for the Obama agenda have mostly focused on the recalcitrant, GOP-led House of Representatives. But Obama's problem may actually be with the house of Congress his party controls. House Speaker John Boehner has signaled that he'll consider proposals that make it through the Democrat-controlled Senate. Based on recent history, that could be a tall order.

Lest you think this is about Republican obstruction of the Democrats' Senate majority via the filibuster, which requires 60 votes to overcome, that's only part of the problem. Note that this period of inaction doesn't quite correlate with the last time Democrats had 60 votes, which was January 2010. And the Senate has actually done plenty of things in the past two years and seven months -- the deals that ended the 2011 debt-ceiling fight and the recent "fiscal cliff," for example, as well as contentious items like the highway bill and the reapproval of the Export-Import Bank.

In other words, the Senate has done big stuff, bipartisan stuff, and controversial stuff. It just hasn't done anything the president could add to his list of policy accomplishments. For that -- the kind of thing a president might talk about in his campaign speeches -- it's been more than two and a half years. (One possible quibble with this argument is the repeal of "Don't Ask, Don't Tell," arguably a major legacy accomplishment for Obama. Even if you count that -- the repeal measure cleared the Senate on December 18, 2010 -- it's still been 795 days.)

Why is this the case? Republicans would say it's evidence of Obama's lack of juice with even members of his own party in Congress, a persistent and extremely well documented phenomenon over the course of the Obama presidency. They also say it's part of a larger pattern of Senate dysfunction that's been obscured by the noisier and even more spectacular dysfunction that plagues the House. As Republicans love to point out, the Senate also has not passed a budget since April 2009 -- it has passed alternative government-funding bills in the interim -- and the last Obama-proposed budget plan received exactly zero votes in symbolic votes in both the House and Senate.

Democrats disagree that this dynamic will kill Obama's second-term agenda. It's true, they acknowledge, that the Senate's bandwidth has been dominated by averting immediate disaster for the last couple of years. But the 2012 election changed everything, they say, and the appetite to tackle big issues has returned. As one Senate Democratic leadership aide told me in an email:

Folks were exhausted from the 111th [Congress of 2009-10] and felt like they needed to shore up their bona fides on deficit reduction after the 2010 results. Plus, we looked across the Capitol at the House and figured there wasn't much point to tossing good legislation into their emboldened maw of the Tea Party.

Now it's different. The House Rs and the Tea Party had their moment and jumped the shark. We feel like we have the upper hand on virtually every major issue, including taxes, and the public overwhelmingly prefers our approach to deficit reduction. Plus we have more seats in both houses. So while I don't disagree that we may not have done a ton in the 112th [2010-11], I would argue that catching our breath then and shoring up our credentials on fiscal issues and taxes has put us in a good position to get a lot of big things done in the 113th.

Immigration and guns are perfect examples, you never saw the kind of bipartisan cooperation that's going on with those two huge issues in the 112th, and we are only two months into the Congress.

Has everything changed? Is the Senate that's been sitting on its hands for the last two years now ready to get moving on big things? The next few months will tell.