It’s been a while since we’ve had a true landslide presidential election. The general definition has been 55% of the popular vote. Clinton’s 1996 reelection comes close, as he did beat Dole by 8.5%, even if he didn’t get a majority of the vote, thanks to Ross Perot’s 8.4%.
When a party has held the White House for two terms, it seems that a close election is likelier than a landslide. See 1960, 1968, 1976, 2000 and 2016.
But 1988 shows that the party in power can win in a landslide if people like the direction the country’s going in, and the other party nominates someone who doesn’t appeal to swing voters. George Bush’s 53.4% isn’t a true landslide, but the closest anyone has gotten in my lifetime. This means, Hillary arguably had the potential for a landslide win last time.
2008 shows the party in power can lose in a landslide if people don’t like the direction the country’s going in. Obama’s 52.9% wasn’t a landslide either, but I would imagine that 2008 would have been worse for Republicans with a Rick Santorum on the top of the ticket, so it could have gone that way.
The other landslides have occurred when a party that’s held the White House for one term gets reelected. See 1964, 1972, 1984 and 1996. This is a possibility for Republicans now, although Trump’s current approval rating isn’t helping.