Check out this graph from the Congressional Budget Office. Look particularly at the dotted line, representing revenues, and notice in the lower portion of the graph how — if the Bush tax cuts are extended (revenues are depressed) — the deficit will persist.

The upper portion of the graph shows how the deficit disappears by approximately 2016 (the end of Obama’s second term, if he has one) if the Bush tax cuts are allowed to expire, as they are scheduled to do.

In other words, if Congress does nothing.