There are reasons why the Founding Fathers rejected direct democracy.
First, they wouldn't see how a direct democracy (i.e.: where everybody decides and vote about everything) could scale on a larger scale than classical Greek city-states and small communities. (Where the dozen, maybe hunderd of decision-making citizen simply gather and discuss together).
Their solution back then was instead to keep the Greek city-state model (have a small bunch of people gather together) except that each one of the gathering people is representative of whole regions/populations/etc. (instead of managing to gather every single person of the huge population in a town's central plazza).
Thus was birthed representative democracy.
It might have sounded good back then, but you see the effect now: the representatives tend to prefer representing whomever pays them the best. Power is back in the hand of the elite and big corporation, only with a thick political layer inbetween.
Well technology marshes on, since founding father, communication technologies have simply been on a constant growth. A rather explosive growth.
Thus later on, you can see whole countries like Switzerland that function on a direct democracy. They have moved on from "Landsgemeinde" (the Hlevetic equivalent of greek city-state gathering in the central place) to direct voting accross the whole country, both in election booth and with voting-by-post.
So even if switzerland is bigger than a greek city-state (currently more than 7m people), thanks to the modernization that existed back then (post & phone & railroad) it has since then been able to coordinate country-wide votation and election very regularily (every few months).
The process is completely open and any one can watch and check.
Now Switzerland is still smaller than other European country or even huge continent-sized countris (like USA, Russia or China, for exemple). But, guess what, technology is STILL marching on and has come up with things like internet and cryptology.
(These are already put into production in some parts of Switzerland. Mainly for expatriate and in a few small commune).
And with these technologies, direct democracy can even scale up to larger populations.
The fear of your founding father about democracy being not practical on anything but smaller greek city-state is simply deprecated by technology.
Other fears against direct democracy usually include that people are stupid and might react stupidly due to mass panic, or because they are selfish and only think about quick personnal profit. Imagine if one would vote about a law for definitely supressing any tax however. People will never vote for tax! The state will go bankrupt!
Politicans know better, let's have them take the actual decision, and have only people voting for politician based on approximate general tendency of them.
Well you've seen the result in TFA's study: Politicians do know better, they specially know better how to earn more money by abiding to the highest paying oligarch.
Meanwhile, direct democracies like Switzerland DO VOTE about taxes, and guess what, big surprise: THEY HAVE VOTED FOR TAX INCREASES, SEVERAL TIME.
Thinking that "sheple don't know, politicians know better" is a horribly condescending paternalistic approach.
Yes, voting blunder can sometime happen (see votation about Minarets, about life-sentences or, more recently, the problems between EU and Switzerland regarding migration freedoms). But they can be mitigiated. At the heart, the main problem is information, if "people don't know" perhaps, instead of deciding for them, you might try to inform them so they make an enlightened decision? Modern communication mean can do help a lot here. Mass media like Press, Radio, TV have been around for decades. Internet is newer and offers even more possibilities for communication (including for minorities which might lack the budget to do it on Mass Media).
Also, patience and time help. People new to Swiss politics might wonder that everything is so slow. Well, it helps staying calm and thinking a bit, and nut rush some policies in a hurry. All the various checks and controls help to diminish the risk that some law is enacted due to mass panic (see you Patriot Act). In Switzerland, it has often happened that a people's motion has been submitted regarding a pressing problem, and by the time it goes through the pipeline, politics had time to adjust and propose a better, "less stupid beause I react" proposition to submit during the same vote. It has often happened that the people committee asking for the vote retract their own proposition because they find the new one better and people only end up voting for/against the one by the state.
And there are also internal checks, Switzerland is a signatory of the human rights convention and other similar international treaties. If any new law is deemed to contradict such international law, the new law can't be enacted (see Switzerland's voting blunder about life-sentences).
Meanwhile, USA has such wonders as Patriot Act, DMCA, etc. law that clearly only profit the corporations or organisation which paid the representative for.