It was 9 months into Nixon's second term (and nearly a year and a half after the Watergate break-in) before more people thought Nixon should be removed from office than approved of the job he was doing. From that point until he was forced to resign those numbers never switched back around. But that was a president who was re-elected with true landslides on both the popular vote and the electoral college and began his second term with an approval rating of nearly 70% before continued events had the public turning on him.
But 2017 is not 1973. Now we are a more polarized electorate. Nixon supporters abandoned him as quick as they could scrape the Nixon/Agnew '72 bumper stickers off their cars. Yes, he had a core group of supporters and some key aids who apologize for him to this day (Kissinger, Buchanan) but everyday voters rarely even admitted they voted for him, let alone expressed a great deal of support. But in 2017 once you've staked out your political turf (and this is especially and almost universally true on the right) nothing short of your candidate having sex with your daughter, stealing your pick-up or mowing down your marijuana grow operation so he can sell his own weed will lead you to turning on him. And for those who want to point out that this is an equal opportunity disease I will remind you that, no it is not.
The proof of this was in the 2016 election. If people who tended to vote for someone because of the little "d" and that was all that mattered, Hillary would have won. But the people who do usually vote for the candidate with the little "d" did not all do that in 2016. Right or wrong (well of course they were wrong) they actually thought things through and voted some other way (or not at all) in 2016. Sure, it's ugly, sure I'm saying you're stupid and lacking in critical thinking skills. but the fact is more right wing voters are sheep than left wing voters. Anyone who doesn't see that simply does not want to. Or is too stupid to.