Let’s say you’re a Republican who is looking with abject terror at the thought of a Donald Trump nomination. You look at poll numbers from upcoming states—Trump by six! Trump by eight! You read and hear about “vectors” and “glide paths”, and you start looking for reassurance that it’s still early, that the last shall be first. Examples abound in sports—didn’t the Red Sox trail the Yankees 3-0 in the 2004 League Championship Series? Weren’t the New York Giants 13 1/2 games out of first in 1951? Surely there are cases where a doomed candidate turned the campaign around, right?

Well…sort of. There are any number of primary campaigns that saw a significant shift of fortunes, but they provide cold comfort for the anti-Trumpeteers. Why? Because 1) they happened a relatively long time ago, 2) they all happened in two-candidate races and 3) none of them resulted in a victory for the come-from behind candidate.

When President Gerald Ford barely beat ex-California Governor Ronald Reagan in New Hampshire in 1976, it might have been seen as a strong showing against a sitting President. But because the Reagan campaign had touted his strength there, the close finish was portrayed as a loss. When Ford won the next four primaries, including a landslide win in Illinois, Reagan’s challenge was on life-support.

In North Carolina, however, a combination of Senator Jesse Helms’ organizational muscle and a half-hour TV speech centered on foreign policy gave Reagan a victory that kept his campaign alive. Over the next 10 weeks, Reagan won 10 primaries, turning the fight into a delegate-by-delegate battle. In the end, the power of incumbency and a last-minute flip by the Mississippi delegation on a crucial rules fight gave the nomination to Ford. We have not seen a genuinely contested nomination fight since.

Ted Kennedy’s 1980 challenge to President Jimmy Carter seemed star-crossed from the beginning. An awful prime-time interview with CBS’s Roger Mudd, the seizure of American hostages in Iran that kept Carter safely in the Rose Garden, and a largely unfriendly primary calendar combined to send Kennedy to defeat after defeat. ...