Obama has more reason to be mad at Johnson and FDR for bequeathing him intractable legacy costs than at Bush: they will substantially reduce the scope of the things that Obama can do. But I don't expect to hear him explain that he has to run a budget deficit because he inherited a legacy of unsustainable spending by his Democratic predecessors. The fact remains that Bush actually left him very little legacy of permanent spending to be drivng his future deficits. Once we withdraw from Iraq (I assume we can all agree that any president would have invaded Afghanistan), and the tax cuts expire next year, the actual net contribution of everything Bush did to Obama's structural deficits will be well under $100 billion a year of the $1 trillion or so Obama is projected to spend.
Not that I want to get all hysterical about the Obama deficits either. I presume he's planning to deal with them, mostly in ways I don't like. But I'm not going to start claiming that I have scientifically proven, through the awesome power of budget math, that Obama is like the worst president ever: I will hate his health care plans, etc. exactly as much if he raises taxes to pay for them. My worries about his deficits are more prosaic: is he borrowing so much money that we're at risk of a fiscal crisis brought on by excess debt and spiking interest rates, or is he crowding out private investments? These are empirical questions, and it's far too early to have more than hints at the answers. But Obama's deficits, even in 2012 and beyond, are the largest since World War II by any measure. And that's good reason to worry, in a non-hysterical fashion.