So why and how has Bush and the Republicans become so dominant in US? Because the Democrats have no spine, and because they're just as corrupt as the Republicans.
See this post in Pressaction about Democract Sen. Dianne Fienstein and her massive profiteering through her husband's business with the War/ Occupation on Iraq. While it's just one example, she is certainly not the only Democrat legislator/ Senator who benefits from criminal actions of the ruling party.
The writer makes a great case why the Democrats deserve so much criticism as the Bush adminsitration. This isn't surprising in any country where there's only two parties competing for power as you either have a situation where the two of them fight tooth and nail and tear the country apart or where the two have a kind of informal arrangement where both parties alternate power after each election or two and both parties commit the same crimes in power with the other one condoning it.