Imagine how bad you’d need to be at your job for your own paid flack to have to reach back 150 years to someone who was pro-slavery to find a favorable comparison.

Which is not to imply, however, that de Blasio is the worst mayor in all of modern-day America. I’ve called him that before, but I think we’d all agree that the competition lately has stiffened, no?

“Why is a member of de Blasio’s own party ripping on him this way?” you ask. Ah, well, apart from the fact that even many Democrats and their media cheerleaders long ago accepted that de Blasio is terrible (which conveniently offered them an unlikable scapegoat for Andrew Cuomo’s even more terrible COVID performance), Rose happens to represent one of the few Republican parts of NYC. That would be Staten Island, which elected him to his first term in Congress in 2018 by less than seven points during that year’s “blue wave” in the House. He’s an impressive guy — veteran, Purple Heart recipient, London School of Economics grad, and owner of a New York accent so thick that it puts mine to shame — but that may not be enough to win against a redder electorate this fall with Trump on the ballot. He needs a little quick-and-easy virtue-signaling to the Republican voters in his district. Result: A quick-and-easy “de Blasio sucks” ad to make them laugh.

But there’s another reason why he wants some distance between himself and de Blasio. Although he’s a centrist Dem who endorsed Bloomberg for president earlier this year, Republicans in his district are naturally trying to capitalize on the locals’ dislike for the mayor.

Rose is locked in a tough re-election battle against Republican challenger Nicole Malliotakis in the 11th congressional district that encompasses Staten Island and southern Brooklyn…

Rose is attacking de Blasio while Malliotakis and the GOP have run ads trying to link Rose to the mayor on issues such as rising crime and anti-police protests. The PBA and other police unions have endorsed Malliotakis.

The GOP also has run ads slamming Rose for voting to impeach President Trump following the Russia election meddling probe.

Rose complained that de Blasio failed to provide a real plan to reopen schools and accused the mayor of “actively trying to kill” New York City restaurants by delaying the reopening of indoor dining.

If you’re worried about being linked to an unpopular politician, calling him the worst ever at his job is an efficient way to try to sever that link.

Speaking of indoor dining, after many months of being barred from that, NYC’s restaurants finally got the green light to reopen later this month at 25 percent capacity. Is the city about to seed a second wave in time for fall or is it now wave-proof after Darth Cuomo’s reign of death and infection? Stay tuned…