But it's not enough, and I'm frustrated. Because our political system only gives us two choices1: a party that allows itself to be rendered ineffectual on a regular basis due to a third of it constantly defecting to their nominal opponents at the drop of a hat, and a party that is working as hard as it can to transfer as much wealth as possible to the corporations and the top 1% while keeping its non-wealthy base distracted with attempts to impose its moral code on the rest of the populace. It gets worse - the Republicans are willing to play dirty, whereas the Democrats are rarely even willing to bring their full range of procedural options to bear2.
There are a lot of really good individual Democrats, but their party leadership is too willing to compromise and rarely seems able to stand up for what they believe in. There are a decent number of upstanding Republicans who aren't trying to screw over the middle class, but their party leadership is at best completely unconcerned about the fate of 90% of the population, and at worst actively evil. It's quite clear that the Republican strategy for this legislative session has been "prevent the Democrats from implementing any solutions, so as to prolong the economic crisis so we can blame it on them for the election". They've said as much - they're more interested in obstruction than any real solutions at this point.
(Edit: And for further examples of the evil pervading the Republican Party, look no further than the recent spate of violence from various GOP supporters and campaign staff. This is how these people think political discourse works in this country: if you don't like what they're saying, shut them up however you can.)
But the choice between "well-meaning but incompetent" and "indifferent and possibly evil" isn't much of a choice at all. I'm voting for the Democrats, because as frustrated as I am with their slow progress in some areas and lack of any progress in others, they're far, far better than the alternative.
And, as unenthusiastic as this defense of the Democrats may be, I have to implore everyone else reading this to consider doing the same. Please don't give the Republicans another shot at fucking this country over.
 Only in exceptional circumstances do independent or third-party candidates stand a chance of election to federal office. Until our system allows me to better represent my preferences, I'll vote tactically every time.
 In the past I've likened the conflict to that between Gryffindor and Slytherin; the Gryffindors have to work harder just to keep up, because they're playing by the rules and the Slytherins aren't, but at least they're generally capable of it. But our current Democratic leadership is more akin to Hufflepuff than anything.