If today’s extremist rhetoric sounds familiar, that’s because it is eerily, poignantly similar to the vitriol aimed squarely at John F. Kennedy during his presidency.
Extremists in Dallas created volatile atmosphere before JFK’s 1963 visit.
This isn't unique to Kennedy or Obama (or Dallas or the South). Reactionaries believed Thomas Jefferson was out to destroy religion and private property. And every "liberal" president since then has had to cope with vitriol and weird conspiracy theories. It's an unfortunate part of the American political climate.