If the Chairman and Ranking Republican Member of the Budget Committee are in such broad agreement on their goals, why don’t they just skip the commission and go straight to their recommendation? That is exactly why Congress created the budget resolution and the reconciliation bill.Of course, the answer to that is that Democrats don't want to cut the deficit now, and Republicans place deficit-cutting far below tax-cutting in their list of priorities. I do think that Kent Conrad, for better or worse, is a sincere deficit fetishist, but most Dems consider deficit size a means to the end of economic growth, not a legitimate goal for policy in and of itself. Republicans, on the other hand, believe in constant tax cuts, period. Their views on spending are hard to decipher, but operationally they appear to be for spending more on the big parts of the budget and cutting spending on the tiny parts of the budget.
That said, I don't understand the second half of Yglesias's post, which is focused on the filibuster. As Baucus said, the filibuster is irrelevant to the deficit: almost all major budget changes (tax cuts, major spending cuts, tax increases) over the last thirty years have been done through reconciliation.
If Democrats want to put off dealing with the deficit for a while (and they might, given the economy), then pushing the issue to a commission that gives Republicans veto power makes a lot of sense. If Democrats want to lower the deficit, then their only choice is to do it alone, through reconciliation, just as they did in 1993 -- and they should expect to get no support at all from Republicans or Tea Party activists who are screaming about the deficit today. The one thing that Democrats can't do is cut the deficit with Republican support.