Has John McCain given up on the idea of being president? How else can you explain him saying that the way the Social Security system works, and has worked since its inception, is a disgrace that he would change if he were elected. Here is a link to an article about this by Washington Post bloggers. [Many newspapers this morning have an AP article about this that puts as favorable a McCain spin as it can on it, but AP does not want bloggers linking to their stories so you will have to find that article on your own.]
All retirees who receive Social Security paid into the system all their working lives, paying the benefits of those then retired, in the expectation of receiving the benefits now. Neither they nor the baby boomer generation who are going to be retiring soon would look favorably on a proposal to change the system so that current workers no longer pay the benefits of current retirees.
The only way the system could be changed that would not be grossly unfair to all the workers who have paid into the system would be for the federal government to inject huge amounts of money into Social Security from somewhere else in the budget to cover the shortfall caused by workers' contributions going into private accounts rather than the general pool. John McCain, as would be expected given his admitted lack of economic expertise, has no idea from where this extra money would come, especially since he plans to make the Bush tax cuts permanent and also balance the budget.
Perhaps he is just tired of campaigning and thinks that touching the third rail of politics will put him out of his misery.