It’s open borders or Nazis, Rep. Alexandria Ocasio-Cortez explained Tuesday, as she placed full blame for the mess at the southern US border on “fascist” President Trump.

In a Q&A posted on Instagram, AOC charged Team Trump with holding illegal border-crossers in “concentration camps.” Leaving no doubt that she was invoking the Nazi death camps, she noted that she was addressing people “concerned enough with humanity to say that . . . ‘Never Again’ means something.”

She left unmentioned that some of those holding areas went up under President Barack Obama, because the unprecedented wave of “undocumenteds” from Central America started hitting on his watch.

Nor did she address the fact that the White House has asked for emergency funding precisely to address the “dehumanizing conditions” in the camps, a bill that has zero funds for The Wall — but Democrats refuse to even vote on it. This, when no less than The New York Times has now editorialized twice urging passage on basic humanitarian grounds.

What does she think Washington should do when 100,000 people a month are crossing the US-Mexican border — then freely surrendering to the Border Patrol and requesting asylum?

The vast majority of those asylum claims don’t hold up, but the avalanche of claims means it takes overwhelmed immigration courts months or years to reach that judgment. Releasing adult migrants into the US interior makes it near-impossible to find them if they don’t show for their hearings.

And US law doesn’t let authorities hold children more than 20 days, yet separating kids from the adults who accompanied them produces its own humanitarian nightmare.

The White House is doing everything it can to defuse the crisis, even successfully bludgeoning Mexico into doing far more to stop the migrants as they’re leaving Guatemala.

Democrats don’t like the camps but refuse to OK funds to upgrade them or to expand the immigration courts to speed up resolution of the claims — and won’t even think about updating laws that never anticipated this situation.

The only “answer” that leaves is to just wave the migrants on in — and, presumably, allow them to collect public assistance just like citizens or legal immigrants do.

If you won’t go along with that, AOC believes you’re just like Hitler.

Fascist. Concentration camp. Never Again. “I don’t use those words to just throw bombs,” the congresswoman insisted. Yet that’s exactly what she’s done.