First, a quick correction based on further reporting: Contrary to the initial reports, the White House’s opening bid for resolving the fiscal cliff included $600 billion, not $400 billion, in proposed mandatory spending cuts. The precise breakdown was $350 billion in health-related cuts, most of which would come from Medicare, and $250 billion in other mandatory cuts. 

That gives the structure of the White House’s proposed deal an evident symmetry: Republicans won in 2010, and they leveraged that win to secure the roughly $1 trillion in cuts in the Budget Control Act. Democrats won in 2012, and they intend to leverage that win to secure the roughly $1 trillion in revenue from the expiration of the high-end Bush tax cuts.