Last month, my colleague Mark Wallace asked a hugely important question: Are we psychologically prepared for the rest of the 21st century? His thesis is that the peace and prosperity we’ve come to assume as ours by right is far from guaranteed. Before long, we may find ourselves tested by dangers we’ve not experienced in many decades, if at all.

Among the possible threats he mentions are war with Russia and the spread of antibiotic resistant pathogens. Other possibilities range from the chaotic collapse of the Eurozone to a devastating cyber-terrorist attack on our communication networks. But perhaps the most disturbing threats are those that aren’t even recognised as a possibility – at least not until its too late. For instance, two or three years ago, who thought that ISIS would end up controlling a territory the size of Britain?

In an essay for Vox, Matthew Yglesias calls into question something that we all take for granted – the political stability of the United States. He doesn’t mince his words:

“America’s constitutional democracy is going to collapse.

“Some day — not tomorrow, not next year, but probably sometime before runaway climate change forces us to seek a new life in outer-space colonies — there is going to be a collapse of the legal and political order and its replacement by something else. If we’re lucky, it won’t be violent. If we’re very lucky, it will lead us to tackle the underlying problems and result in a better, more robust, political system. If we’re less lucky, well, then, something worse will happen.”

His argument is that presidential (as opposed to parliamentary) systems are unstable:

“To understand the looming crisis in American politics, it’s useful to think about Germany, Japan, Italy, and Austria. These are countries that were defeated by American military forces during the Second World War and given constitutions written by local leaders operating in close collaboration with occupation authorities. It’s striking that even though the US Constitution is treated as a sacred text in America’s political culture, we did not push any of these countries to adopt our basic framework of government.

“This wasn’t an oversight.”

Whereas parliamentary systems work in such a way as to bring conflicts between governments and legislatures to a resolution – for instance, through fresh elections – the American system does the opposite:

“Since both the president and the Congress are directly elected by the people, they can both claim to speak for the people.”

One can object that despite a political system that tends towards paralysis, America is a notably dynamic country. In a decentralised nation of fifty states, in which government isn’t that big to begin with, a great deal can happen without the say-so of national politicians. The unique character of America’s party system has also allowed informal coalitions to be built across party lines:

“For much of American history, in other words, US political parties have been relatively un-ideological and un-disciplined. They are named after vague ideas rather than specific ideologies, and neither presidents nor legislative leaders can compel back-bench members to vote with them.”

Unfortunately, the give-and-take of previous decades is giving way to an era of ideological polarisation. The conservative Democrats and liberal Republicans of old are all but extinct. The last time that the parties were so divided on matters of principle was in the 1850s, a precedent that Yglesias describes as “not enormously encouraging.”

He isn’t suggesting that a second Civil War is on the cards, but he does see the political situation going from bad to worse:

“…over the past 25 years, it’s set America on a course of paralysis and crisis — government shutdowns, impeachment, debt ceiling crises, and constitutional hardball.”

To get anything done, recent Presidents have made moves that “do not violate the letter of the law, but do trample on our conventional understanding of how it is supposed to work.” Sooner or later, this will result in a full-blown constitutional crisis.

Before we reach that point, it worth noting that important things are being left undone – in particular, action to tackle the country’s colossal deficit and the pursuit of an effective foreign policy. America’s political paralysis is therefore something we all need to worry about.