Thoughts:
(a) and (b) are, of course, not unrelated. We have a political structure that makes it hard for the government to do big new things through Congress. The Klein/Yglesias argument might be restated as “The Constitution was written for people a lot more anti-statist than we are today,” which I think is true.

As I read them, Ezra's and Matt's point is that, given the following options:

“The United States, virtually alone among industrialized nations, does not have universal health care. This is properly understood as:

(a) Americans are uniquely committed to libertarian / conservative / anti-statist policies generally, and/or uniquely distrust the government when it comes to provision of health care;

(b) America's bicameral political system, combined with the rules of the Senate, makes it uniquely difficult to pass major legislation of a type that is similar to provision of universal health care.”

Matt and Ezra are arguing for (b), and thus against (a).

I think it's an interesting argument and well worth considering.

As for the “Republican ideas would also be more likely to pass” retort:

(i) maybe so;
(ii) if so, it doesn't undercut the point Matt and Ezra are making, but only the points that their critics think they ought to be making;
(iii) the Democrats have not been nearly as pro-active w/r/t using the filibuster, which gave the Repubs the ability to pass major legislation with only 50 votes in the Senate under GWB. The Republicans appear to be uniquely good at obstructionism … or the Dems uniquely bad. Not sure which.

So a question for Paul Z and others: what do you think a unicameral legislature would have allowed the Repubs to accomplish, that they didn't, over the period 2000-2008?

The countries that do have universal healthcare don't give it up; and, they don't tend to have the kind of supermajority requirements that the US does.

I once read a piece (a couple of years ago) where the author remarked on politicians' and political writers' general behavior in the discussion of foreign policy. For some reason, this area is more likely to avoid such sweeping magical and one dimensional switcheroos of factors because people are more ready to acknowledge the “butterfly effect” in that area. Of course, he also proposes that this correct perspective is done for the wrong reason. His idea is that people avoid ignoring the butter fly effect in FP because our government doesn't control the realities created by other governments' or countries' actions. I agree with him that this simply isn't a good reason to view the matter more correctly.

In closing, let us stay for a sec in their one dimensional, “non-intercausal”, chain-reaction-free zone:

I wonder how many times Matt and Ezra thanked the maker during most of the 2000s when the GOP had control of both houses and things they didn't like didn't pass. I was quite relieved myself on many instances. I often wish everything needed an 75% majority. We'd see some serious rule changes then.

Anyway, if we had a unicameral legislature, Bill Clinton would have been removed from office. So would Andrew Johnson, for that matter. All black people would still be Republicans (but urban Jews would still, in my counterfactual, be Democrats), and Matt Yglesias's life would be constant disappointment, as his party would be confined to handful of urban enclaves.

Is your position that counterfactuals are silly or just this particular counterfactual is silly? Or both?

It strikes me that you've probably gone on at length about this subject somewhere, and if that's the case you need not rehash it for my sake.

But Yglesias's hypothetical isn't concerning itself with a full-on Butterfly Effect analysis–he's holding most of history constant to make a smaller point…

Universal healthcare has been in the pipeline of liberal dreams for a long time. It stands to reason that it would have probably happened by now if a supermajority weren't required. And once you give voters something like that, it's really hard to take it way (see: Medicare), so it's also somewhat unlikely the opposition could have amassed its own 51% majority several cycles later to repeal it.

Oh well, I said something about Klein wanting a tyranny of the majority, unless the Republicans gain power, then it wouldn't do.

Bottom line, the Senate and its rules are the chief obstacle, rather than Obama's perceived lack of $FAVORITE_IDEOLOGICAL_BENT