Whoops the US Government

For much of the 20th century, America's two major political parties were ideologically diverse. The Republican Party included both Barry Goldwater and George Romney. The Democratic Party included both Strom Thurmond and Eugene McCarthy. The spread of political opinions in each party made it cross-aisle deals easier and organized, extended party warfare harder. Bipartisan votes were common. Filibusters were rare.

But in recent decades the parties have polarized. According to the respected DW-Nominate system, which measures party polarization, the two parties have never been further apart in Congress.

There's nothing inherently wrong with that. It makes sense for Republicans to agree more with each other than they do with Democrats, and vice-versa. But our political system wasn't built for polarized parties. (In fact, it wasn't built for parties at all — the Founding Fathers hated political parties, even though they went on to start a few of them.) The result is deep governmental dysfunction as a system that requires bipartisan cooperation collides with political parties that can't cooperate.

...Look around. Almost no other countries have our system of government. That's because our system of government is pretty unstable. "Aside from the United States, only Chile has managed a century and a half of relatively undisturbed constitutional continuity under presidential governments," the late, great sociologist Juan Linz wrote. "But Chilean democracy broke down in the 1970s."

Systems like our own have a broad tendency toward instability and partisan conflict because a democratically elected executive can come from one party and a democratically elected legislature from another. Both sides end up having control over some levers of power, a claim to be carrying out the will of the public, and incentives that point in opposite directions. That's very different than the kind of system you see in, say, the United Kingdom, where only one party controls the government at any given time.

"We can say with at least some certainty that if highly divided countries adopt executive-centered presidential systems, then they are probably making a mistake," Robert Elgie of Dublin City University concludes.

The secret to the American political system's stability was that our political parties were unusually mixed and so they didn't have the typical incentives toward flat-out conflict. In other words, we weren't a highly divided country. But that's no longer true. And so our system is beginning to exhibit the predictable, and terrifying, tensions of all presidential systems.

—Ezra Klein, in "The 13 Reasons Washington Is Failing." Emphasis mine.