I never really noticed, but the promise of privatized Social Security has always been there with the Bush team, just waiting for the right moment. I was surprised to hear about it during the debates, until I was informed that it's been in each of his State of the Union addresses. After doing a quick search, sure enough, there they were. You can bet if re-elected he'll go after them hard. Here are the mentions by year:

2004 : Younger workers should have the opportunity to build a nest egg by saving part of their Social Security taxes in a personal retirement account. (Applause.) We should make the Social Security system a source of ownership for the American people. (Applause.) And we should limit the burden of government on this economy by acting as good stewards of taxpayers' dollars.
2003 : A growing economy and a focus on essential priorities will also be crucial to the future of Social Security. As we continue to work together to keep Social Security sound and reliable, we must offer younger workers a chance to invest in retirement accounts that they will control and they will own.
2002: Retirement security also depends upon keeping the commitments of Social Security, and we will.  We must make Social Security financially stable and allow personal retirement accounts for younger workers who choose them.