It tells you something about the state of the party when the main voice calling Democrats to sanity isn’t even a member: It’s Sen. Bernie Sanders, that proud Socialist.

Don’t get us wrong: Bernie’s economics are as cockeyed as ever. Still, he’s been playing the moderate against Democrats’ current chairman, Tom Perez, and a former one, Howard Dean — who was himself once the party’s presidential runner-up.

Sanders’ disagreement with Perez actually started while the two were doing a series of joint speaking gigs, a supposed “unity tour.” At the senator’s request, the two added a rally for Heath Mello, a promising candidate for mayor of Omaha, Neb.

Then pro-choice hard-liners noted that Mello used to be a pro-lifer and still says he’s personally opposed to abortion for religious reasons. Ilyse Hogue, the head of Naral Pro-Choice America, denounced both Sanders and Perez for backing “candidates who substitute their own judgment and ideology for that of their female constituents.”

Perez instantly surrendered, saying: “I fundamentally disagree with Heath Mello’s personal beliefs” on abortion, congratulating him for giving up on writing those beliefs into law and warning, “Every candidate who runs as a Democrat should do the same.”

Should every voter who’s uneasy cheering for Planned Parenthood switch to the GOP?

Look: Democrats never would have passed the ObamaCare law without the votes of sort-of-pro-lifers like Sen. Bob Casey (D-Pa.). (Of course, several of those politicians felt betrayed when Team Obama used it to mandate abortion and contraceptive coverage, but that’s another story.)

“You just can’t exclude people who disagree with us on one issue,” Bernie warned. He stuck with Mello, because 1) mayors don’t have much to do with abortion anyway, and 2) the left will never win majorities if it insists on thought control.

Which brings us to his flap with Dean.

After UC-Berkeley nixed that speech by conservative firebrand Ann Coulter, the one-time Democratic Party boss, presidential wannabe and Vermont governor tweeted: “Hate speech is not protected by the first amendment.”

He was dead wrong, of course, and his tweet got pretty much everyone — legal scholars, fact-checkers, pundits, pols, on both the left and right — to correct the record: Not only does the First Amendment make no exceptions for “hate speech,” its whole purpose is to make sure Americans can say hateful, unpopular things.

Heck, why would anyone need a Constitutional right to say only things no one objects to?

As Sanders put it: “Ann Coulter’s outrageous ― to my mind, off the wall. But you know, people have a right to give their two cents’ worth, give a speech, without fear of violence and intimidation.”

When even Bernie Sanders says you’ve gone off the deep end, you can be pretty sure you have. Too bad so many Democrats need the reminder.