From the Wall Street Journal's interview of President Bush:

WSJ: Can I ask about Social Security? You mentioned it in your speech. You also talked about low taxes being important to the strength of the economy. Would you accept an increase in the Social Security tax income cap from present levels in order to get a [reform] deal?

GWB: I want people to bring their best idea to the table, and I'm bringing my best idea, which is you don't have to raise taxes to solve Social Security.