It isn’t that people are less intelligent than before, it’s that we’ve slowly eroded the aristocracy that was supposed to protect us from ourselves: the electoral college is a non-sapient mechanism at this point, Senators are directly elected, and many judges are directly elected. The House was always intended as a playground for demagoguery and polemics, but now that the Senate and Presidency and judiciary are as well, there are no more arms-length gatekeepers. The parties that control the country have no incentive to make wise decisions, only popular ones… and then, only popular enough to win roughly 30% or so of the population, that portion that constitutes a majority of the voters.
Direct democracy has always been a bad idea, and in some case it’s because of a parallel issue that libertariaism has: you can’t expect the entire populace to be plugged-in dispassionate arbiters of social, political, l and legal issues, just like you can’t organize a society around everyone being good little capitalist marketeers.
The aristocracy of the Constitution – a republic, in that the aristocracy ostensibly is vulnerable to some popular rollover – was trying to thread the needle between mobocracy and oligarchy, and somehow both ends of the equation have managed to find and distill the worst elements of both.
What’s interesting about this is that the original system was supposed to be full of checks and balances, governmental factions existing in a creative tension, pulling against each other to tease out an optimized government. That’s a great idea, but in modern times that’s become just another system to solve. The system has been slowly eroding these impediments to efficiency – eroding the tensions, smoothing the process – but in doing so, they’re breaking the end result. The system wasn’t supposed to run smoothly, it was supposed to create good government. By emphasizing the smoother operation and selection of various governmental representatives, all it’s done is shift the tension from being between branches with differing methods and oversight to a tension between political parties, and in doing so the various branches of government are themselves existing within a tension, unable to present a united front for consideration by the other branches.
The creative tension between branches is now a destructive tension within branches. Congress can’t legislate. The President acts with increasing impunity, knowing the Executive can’t be stopped by a feckless Congress and inspired to act and fill the gap of Congress’s dysfunction. The judiciary is forced to resolve issues which ought to be resolved by legislation. It’s a decent lesson in systems maintenance: you’d best fix one thing when it starts to rattle, because that rattling is going to break two or three other things, which will break two or three other things.