Much as I hate to say it, probably so:

If the GOP really believes that they can get to anything close to a sustainable budget without raising taxes at least a little bit, then they are spending too much time reading their own press releases, and far too little time talking to voters outside of their tea party base.  I think it's probably possible to do more, on balance, with spending cuts than with tax hikes--but not all. Mathematically, it's certainly possible--but politically, it isn't.

via Do We Really Need to Raise Taxes to Close the Deficit? - Megan McArdle - Business - The Atlantic. See also my take on it from last year: