>We have never heard of a coup in a rich old democracy
There was a successful coup in France in 1958: https://en.wikipedia.org/wiki/May_1958_crisis_in_France
At that point France had been a democracy or democratic republic for 88 years. (I'm not counting the First Republic because it was chaotic and included the Reign of Terror. I'm not counting the Second Republic because it lasted only 4 years and was sandwiched between longer-lasting intervals of dictatorship and monarchy. I am counting the Nazi occupation because I consider its cause to have been external to France and thus not a sign that French democracy was deficient. Also, it was sandwiched between much longer intervals of democracy.)
Then again 88 years is not 231 years, and there were much stronger signs (namely, the "recurrent cabinet crises" described by the Wikipedia article) in the years leading up to 1958 that the French system of government was unsatisfactory than there have been so far IMHO of the unsatisfactoriness of the US system (and one of the effects of the coup -- in addition to a new leader -- was a new French constitution).
(Also, IIUC the coup was basically bloodless.)
Great point! I missed that important example, thank you.
Two notes on military coups, as the French coup illustrates.
A US coup would almost certainly require escalating political violence outside the military to polarize our anti-praetorian, moderate military. IIRC the officer core is Republican leaning but with plenty of Romney Clinton’s (some magazine survey).
There's generally a simpler explanation in this case that Trump and the Joint chiefs of staff have had a rocky relationship, so the military has no interest in assisting a coup attempt, even if they are willing to renounce democratic norms (they are sworn to protect the constitution, after all). Without cooperation from the military a coup is a non-starter.
Several commenters have argued that a Trump might attempt, or even succeed, at remaining in power despite his electoral defeat this year. Here are soem example articles
The Nation Chicago Tribune Japan Times
Most people dismiss these claims. We have never heard of a coup in a rich old democracy, so we dismiss it as "too weird to be possible". As rationalists, we know this argument proves too much. By the same argument a man in 1919 could have argued a fascist germany is impossible, or a man in 1780 that flight would be impossible.
Then what exactly is the reason that a coup is unlikely in the US? To answer that question, I will sketch two game theoretic arguments about why coups occur and why democracies reemerge from them.
To start with, a successful elite pact must be self-enforcing. Elites that choose to break the pact must face costs which keep them cooperating. There are real costs to a party that chooses to forsake democracy, and these costs are often higher than the cost of losing power.
For a party leaving power, the following inequality must hold
Where is L is the utility of losing, W is the utility of winning the next election, S is the utility of subverting an election, and p is the probability of winning the next election. Because , the expected utility of leaving power depends on the probability that the party will win the next election.
Does Mitch Mcconnell think he can win the 2024 election? Yeah, he probably does. Recessions are quite common, he just gained in the house, and he holds the senate. Because he holds the senate he can prevent any bills from passing, increase policy drift, get people pissed off at the government, and increase his chance to win 2024.
Furthermore, if the Republicans wanted to launch a coup, 2008 would have been a more favorable year. Bush Junior had strong relations with the party legislators and the lose was large such that p was low. So Republicans are very unlikely to participate in a subversion attempt.
The Weingast model is a bit more complicated, see here for full diagrams. Imagine a sovereign S and two citizen groups A and B. S would like to transgress against the citizens, taking half their utility and destroying half. A and B want to protect their utility. If A and B both revolt in the same round, they overthrow S. If only one revolts, they pay a penalty and the revolt fails.
In an iterated game under rational actor assumptions, there are only two stable equilibria. If the sovereign realizes that she can transgress against one group without the other group revolting in cooperation, she can achieve an equilibrium of constantly transgressing. The only stable way to avoid this equilibrium is for both groups to agree to police transgressions against one another. Constitutions area common mechanism for doing this.
America almost certainly still has the institutional capacity to do this. Yes, America's social capital is declining (paritcularly now with social distance). But without a strong base of institutions becoming the world's wealthiest country is impossible. Furthermore, the strong federalism and localism in the US grealty helps resolve this problem. The resurgence of governors during the COVID crisis is a great example.
If I have time I'll come back and add another model.