CBO’s bottom line is thus simple: tax revenues will rise faster than the economy even if Congress does nothing new. Indeed, revenues may rise faster than the economy even if Congress enacts substantial tax cuts. Our long-run fiscal dilemma exists because the scheduled growth in future spending is even larger than the scheduled growth in future revenues.
via Why Taxes Are Going Up « Donald Marron [emphasis added].
The problem isn’t raising more or spending less, it’s doing enough of both and living within our means. People says deficits don’t matter, but at some inestimable point, they do. It’s systemically safer to live within our means (bring our deficit spending and debt closer to zero,) than to approach that catastrophic, unknown number somewhere north of where we are now.