I've heard this expression from so many people over the past two weeks, including some who are politically savvy. What world are you living in?
If Hillary Clinton wins the presidency, it's not going to end. Donald Trump might refuse to accept the results of the election. Although this might lack any foundation in law — unless the Republican Party had ground to challenge specific state results — it would embolden his hardcore, alt-right supporters. To do...well, they have the guns, don't they?
If she wins but Democrats fail to gain a majority in the Senate, it's not going to end. Republicans have stated explicitly that they will refuse to approve any Supreme Court nominee she puts before the upper house. President Obama's highly qualified, centrist-to-a-fault nominee Merrick Garland has not even been granted a hearing before the Senate.
This is only the beginning. The scorched-earth nihilism shown by a disciplined Republican Congress will only intensify if the party loses the White House yet again. Clinton's cabinet and agency nominees could conceivable be blocked for the next four years. The GOP will stop at nothing, because its members believe only they have the right to rule. This was the party willing to default on U.S. debt and bring on world depression to stick it to That (Black) Man in the White House. Its austerity has prolonged the suffering of millions.
In the elevator, a veteran politician said that Hillary had the ability to get things done LBJ-style. With all due respect, LBJ had solid Democratic majorities in Congress, a mass Republican party with plenty of liberals and centrists, the American liberal consensus still intact, and the nation's sympathy for the martyred John F. Kennedy. None of those things appertain today.