I am probably one of the few liberals who don’t think the Tea Party caucus is engaged in irresponsible hostage-taking. Sure, I disagree with their policy objectives, and they are risking economic catastrophe by trying to force the government into default. But they are also fighting for a principle, misguided as it may be: Obamacare is evil, and should be stopped. The debt ceiling is an absurdity that should not exist. But since it does exist, it is leverage that conservatives can use to try to achieve their policy goals. The problem is that the debt ceiling exists; given its existence, you can’t blame people for using it for their ends. It’s like the filibuster: you can say that the 60-vote requirement is bad, but you can’t blame people for taking advantage of it. As Norman Ornstein said..., “If you hold one-half of one-third of the reins of power in Washington, and are willing to use and maintain that kind of discipline even if you will bring the entire temple down around your head, there is a pretty good chance that you are going to get your way.”
I don't think that the fact that something is permissible under existing rules necessarily makes it OK. Unlike the public, legislators have the power to change laws/rules that allow behavior that shouldn't be permitted, that's their job, and I don't think threatening the economy with severe harm to get your way ought to be allowed. They aren't operating in a world where the rules are determined exogenously, so they can't just say the rules are the rules and we are simply operating within them -- the rules can (and should) be changed.