American democracy is doomed ('constitutional hardball' is a great way to describe the 'modus operandi' of the Trump-McConnell GOP.)

This is how the American system of government will die

I found their predictions to be kinda interesting (and clearly minimal)

The best-case scenario is that we wind up with an elective dictator but retain peaceful transitions of power. This is where I'd place my bet. Pure parliamentary systems, especially unicameral ones, give high levels of power to the prime minister and his cabinet, and manage to have peaceful transitions nonetheless. The same is true in Brazil, where the presidency is considerably more powerful than it is in the US.

But parliamentary systems also feature parties that are stronger than their leaders, which serve to prevent single individuals from garnering too much power. America's parties are getting more polarized, but they still aren't as strong as those of most other developed nations.

The worst-case scenario is if the presidency attains these powers and someone elected to the office decides to use them to punish political enemies, interfere with elections, suppress dissent, and so forth. Retaining an independent enough judiciary is a guard against this, but only if norms around obeying its rulings are strong. And, unusually, America allows for true independents, undisciplined by their parties, to become heads of government.

The US political system is not gonna collapse. It's gonna muddle though (A pretty interesting take. There are problems but people won't try to fix them but instead become disengaged and kinda forget about it.)

I think one of the things the authors missed while writing these this is how news became partidarized in the same manner, thus allowing outlets like Fox News to just consume the Republican electorate. They also missed how voting has been targeted too, and underestimated how willing the public was to act and how would the public react to this, which was by electing someone who didn't care about said broken Congress (or any sort of constitutionality), which is what became of Trump.