Paul Krugman gets to the heart of the matter:
If one thing is clear from the stimulus debate, it’s that the two parties have utterly different economic doctrines. Democrats believe in something more or less like standard textbook macroeconomics; Republicans believe in a doctrine under which tax cuts are the universal elixir, and government spending is almost always bad.
Which means Broderism (i.e. bipartisan agreement) is impossible. It's like getting a doctor and Christian Scientist to agree on what to do with a sick person. Can't be done.