My comment, submitted to Krugman's blog
I view this offer by Obama as the latest in a long series of actions by DLC members and other "centrists" to kill the liberal wing of the Democratic party and consolidate power for themselves. Making cuts in Social Securiity while simultaneously raising taxes on the middle class (and let's be clear, that's the effect of this change to Chained-CPI) is going to be a political disaster, and will kill any credibility that the party has with anybody moderately liberal. As a liberal, I had already decided to not vote for Obama based on my belief that he would do exactly this (and exactly now). Obama has no credibility with me now, and his continuing embrace of conservative policies will only further demoralize liberals.
This is a time in history when the party should be moving to the left with a lot of power. Politically, the opportunity is there. The country has been following conservative policies for at least the last twelve years, and the results have been disastrous. The deregulation of the 90s has led to the profiteering of recent years, and that has led to the market crashes and the "need" to bail out the banks. None of this has been good for the middle clash.
So, with that as backdrop, Obama's genius idea is to simultaneously preserve the Bush tax cut framework for those earning up to $400k/year while cutting social security brackets and effectively raising taxes for all taxpayers.
Looking forward to the next time the terrorists of the House Republican Caucus use the debt ceiling to threaten financial disaster.