Several of these people say they support action to curb climate change. That can’t happen without filibuster reform. Several say they support comprehensive immigration reform. That can’t happen without filibuster reform. Several say they support a public option. That can’t happen without filibuster reform.This is not correct. The public option certainly fits within the rules of reconciliation. Either cap-and-trade or a carbon tax would almost certainly fit within reconciliation (although there are some complexities there). Immigration reform, I agree, could not be done through reconciliation (although I don't think liberal immigration reform has any chance of simple majorities in both Houses of this Congress, anyway). Should the Democrats do well this November, it's certainly possible for them to actually pass an FY 2012 budget in Spring 2011 with reconciliation instructions allowing for a bill with both public option and major climate change provisions, and to need only simple majorities to get that bill to the president. Indeed, it would even be protected from non-germane amendments, which would not be the case for a regular bill in the Senate.
And it's worth pointing out that it's a perfectly coherent position to support substantive change but also support current Senate rules -- even if those rules make change (in any direction) less likely. Yglesias has consistently argued for majoritarianism both on its own merits, and on the basis that liberals are better off risking conservative action in years like 2003-2006 as long as liberals can have their way when circumstances favor them. On the former, I'll continue to disagree with him (although I think both of us would agree that there would be plenty of other anti-majoritarian elements in the American system of government even if things routinely passed the Senate with 51 votes). On the latter, well, he could be right -- or not! I don't think it's at all obvious that liberals are better off in the long run if party majorities are stronger to act in the Senate, and therefore I don't think it's correct to imply that someone who takes the other view isn't really for liberal priorities (or, a few years ago, that Gang of Fourteen Republicans were obviously not true conservatives).