Tom Coburn's decision to take a break from the gang of six, the bipartisan group of senators who have been discussing ways out of the current fiscal impasse, is a significant setback. Expectations that the main alternative forum for this discussion--Joe Biden's panel--would get somewhere on the long-term issues have been low from the outset. Quite recently, the gang of six looked the best bet.
Coburn is a key figure because he is a conservative cut-spending Republican, who commands credibility with that part of the political world; but he was also willing to consider tax reforms (like those suggested by Bowles-Simpson) that raised revenues while lowering tax rates, thus arousing the ire of no-tax-increase hardliners such as Grover Norquist. Coburn is that very rare thing in Washington, a genuine fiscal conservative. To see him give up is worrying.
However, the news is not necessarily bad for the prospects of getting the debt ceiling lifted. The gang of six's deliberations, and the hope they sustained of a larger breakthrough, were serving as an excuse for further delay on that immediate question. The sidelining of the gang of six could accelerate talks in the Biden group and elsewhere on a patch, leaving the underlying problems for later. That is what both sides now seem to want. Raising the debt ceiling as soon as possible is a worthy goal. Agreeing to disagree on the longer-term issues, as though these can wait another two years (or more), is not.