Note: When I refer to the Democrat party I am referring to the post-reconstruction party not its previous incarnation in the south before the civil war.
Historically the Democratic party has been a large tent party which supports labor, the middle class, and equal rights for minorities/women. Democrats were the primary driving force behind the civil rights legislation and women's suffrage as well as entitlement programs that benefit the poor and middle class. Democrats have also traditionally supported immigration reform and a women's right to choose, however there has always been more variation in beliefs for these two issues.
The current incarnation of the Democratic party resembles the historical democratic party in the same way a chiuaua and a malimut resemble each other in that they are both dogs. The current Democratic party insists on compromise to the point of complete ineffectiveness. When the Democratic weakness is combined with the insane radicalism of the Republicans, the result is that the Democrats are no longer liberal nor progressive but rather centrist. Democratic politicians seem largely incapable of showing any spine either in defense of their views or their fellow Democrats. Ironically, Anthony Weiner, one of the very few Democrats to show any balls on the floor of congress (http://www.youtube.com/watch?v=5XsQg3JoMZ0) was essentially ejected from the congress for twittering pictures of said balls over the internet. The Democrats have gradually been pulled over to the right through compromise and refusing to draw a line in the sand. To the Republicans and corporate interests Democrats are essentially one of those blowup-punching bag clowns; irritating, impossible to completely knock over due to the heavy base re-righting it, but at the same time completely incapable of fighting back or protecting itself. Somehow some of the deals between the Democrats and Republicans end up with the Republicans getting more than the initially asked for (debt ceiling Reid plan, budget debate, etc.). Unfortunately the Democratic party is by far the best choice for political representation in the current national debate because while they are severely flawed, they are the only thing standing against a group which actively wants to destroy the US government and install a cross between a christian version of the Taliban and an Ayn Randian dystopia.
While the Democratic party is weak, ineffective, and makes deals which even the average middle school student can see border upon complete capitulation, they have one thing going for them: they are better than the other side.
The Sarcastic Liberal