Finally, a Republican steps forward, repulsed by what the boorish incumbent president has done to sully the storied Party of Lincoln and Reagan, and announces a challenge for the 2020 GOP nomination for the presidency.

And that man is … William Weld?

The peripatetic onetime prosecutor and former governor of Massachusetts (and briefly candidate for New York chief exec) isn’t who we thought might be the first Republican to dare tell the emperor that he has no clothes and remind the party that it once championed limited government, fiscal responsibility, the rule of law and character counting above all.

Given the shape of the GOP now, Weld has approximately as much of a chance as Lincoln himself of actually grabbing the nomination. But he could cause headaches in Massachusetts neighbor New Hampshire, home to the first primary.

At an event there Thursday, Weld didn’t mince words, calling President Donald Trump a “schoolyard bully” (check), “unstable” (check) and “a president whose priorities are skewed to the promotion of himself rather than toward the good of the country” (check and double-check).

More important, Weld might inspire other Trump critics. What about it, former Ohio Gov. John Kasich? How about it, ex-Tennessee Sen. Bob Corker? What say you, current Nebraska Sen. Ben Sasse?

The water’s fine. Jump in.