Unprecedented. That word has been tossed around a lot since Donald Trump decided to run for president. Whether or not it has been overused, it certainly applies to the volume and scope of the scandals in which he has been embroiled since 2016. Presidential malfeasance is not new, but as historian Marc Horger traces, Trump's scandals have wrapped up all the different kinds of disrepute into one tangled web to an extent that is, well, unprecedented.