Here’s an expressive chart showing the reasons the deficit is too high:

From the source:

The events and policies that pushed deficits to these high levels in the near term were, for the most part, not of President Obama’s making. If not for the Bush tax cuts, the deficit-financed wars in Iraq and Afghanistan, and the effects of the worst recession since the Great Depression (including the cost of policymakers’ actions to combat it), we would not be facing these huge deficits in the near term.

In short, take away Bush’s two wars, his tax cuts mostly for the wealthy, the bad economy he generated, and therefore the need for stimulus to keep it from becoming a depression, and we’d practically have a balanced budget.

In the meantime, Republicans are adamant that we continue with the Bush tax cuts–the one element which, over time, will balloon the deficit more than anything else. And when the deficit falls somewhat over the next several years, Republicans will inevitably claim all the credit, and demand they get everything they want in the name of cutting the deficit more–which would in turn explode the deficit again, which they would then blame on Obama and/or the Democrats. And so on and so forth.