In my Inbox this morning from NBC's First Read—

[T]he Wall Street Journal runs a memo from Bush's director of strategic initiatives to conservative allies outlining how private investment accounts must be accompanied by benefit cuts, and emphasizing, "the current system is heading for an iceberg." The scope of the distribution, and whether the White House wanted the memo to get out, are unclear. [emphasis added]

I would go for the WSJ article, but I don't link to sites that don't offer free registration.