Non biased view (as best I can do):
The Republicans are typically conservative, pro small government, religious. They are the "right".
The Democracts are typically liberal, pro large governments (taxation), non religious. They are the "left" of US politics.
---end of non biased view
And the problem with Democrats is that their campaign advisors are stupid and they are behind the times. The Republicans always win because they are good at convincing people that what the Republicans want is what's good for them. For instance, estate tax (random example, it's not necessarily true, but it's how they work); the estate tax only cuts taxes for rich people (typically Republicans) - it has NO EFFECT on poor people. But Republicans spin it so that they get people to believe that because they're cutitng taxes for the rich, they're helping them, either because when those poor people "eventually get an estate," they will have to pay less tax. Or they make them think that they're reducing taxes for everyone, or that a lowered estate tax sets a lowered tax precedent (witness the tax cuts for everyone, but the significant tax cuts for the rich).
Basically, Republicans are good at convincing everyone that their agenda is best for them
The Democrats, while they have good views (IMO), are freaking retarded. The reason Gore and Kerry lost was because they were blindly following their pollsters and campaign advisors; so they didn't show any personality. They showed what the Democrats thought was the correct and calculated "posture" for whichever audience they were talking to. Thus, they came off as fake and non-personable. The Democrats are also worse at raising money than the Republicans, and are absolutely pathetic at mudslinging. The Republicans can turn a blow job into Armaggeddon, but the Democrats can't turn a botched and bloody war into more than a fizzle.
I like the Democrats, but they're retarded at politics. Watch; election after next, Republicans will probably come back strong.
EDIT: And a lot of people in the rest of the world (and in the United States, too), are confused about what our government actually is. We're not "one country" per se, we're 50 smaller countries bound together in an agreement that we can't get out of. I've seen here (on HLP), a lot of foreigners (and again, US citizens) express shock or suprise or just plain confusement when they see a state going in a completely opposite direction as compared to the Federal Government. You have to realize; the USA is the United States, while the Federal Government has overarching power, it does have limits, and the state can actually supersede the feds in certain circumstances.