Where in the blazes were the rest of the Democrats on the stage when Israel was brought up in Charleston? How could they let slide Senator Sanders’ libels of its elected premier? It took none other than Israel’s foreign minister, Yisrael Katz, to put Senator Sanders’ dishonest, ad hominem remarks on Israel into proper relief — as so “horrifying” that those who support the Jewish state would be unable to support Senator Sanders for president.

The dustup in Charleston was a reminder, if one were needed, that the Democratic front-runner is cut from the same cloth as the leader of the Labor Party in Britain, Jeremy Corbyn. He is another socialist who for years spent his political capital apologizing for Israel’s enemies. It’s hard not to conclude that one reason Mr. Corbyn’s party met a historic defeat was the hostility to the cause of Zion.

In Charleston, it was CBS’ Washington leg, Major Garrett, who put the question to the Democratic front-runner. He noted that if elected, Mr. Sanders would be America’s first Jewish president. “You recently called a very prominent, well-known American Israel lobby a platform for, quote, ‘bigotry,’” Mr. Garrett said. He then asked, among other things, whether Mr. Sanders would “move the U.S. embassy back to Tel Aviv?”

“Let me just — the answer is, it’s something that we would take into consideration,” Mr. Sanders burbled, adding: “I am very proud of being Jewish. I actually lived in Israel for some months. But what I happen to believe is that, right now, sadly, tragically, in Israel, through Bibi Netanyahu, you have a reactionary racist who is now running that country.” In reaction to which the Democratic audience broke into applause.

It was a breathtaking moment. What Mr. Sanders vowed to take into consideration, after all, is reversing a move of the American embassy to Jerusalem that was carried out by President Trump on the basis of an almost unanimous decision of the United States Congress. The vote was 374 to 37 in the House and 93 to five in the Senate. Vice President Biden, a co-sponsor of the legislation, was cowed in Charleston into silence.

Plus, for Mr. Sanders to say on national television that he “actually lived in Israel for some months” without giving the context . . . well, it is completely disingenuous. It is true that he lived on a kibbutz. It was not, though, just any kibbutz. The name of the kibbutz was what Israel’s leading liberal newspaper, Haaretz, called “one of Israel’s best-kept secrets.” It turned out to be a kibbutz called Shaar Haamakim.

We wrote about this four years ago, when we quoted the Times of Israel as marking that the kibbutz belonged to an Israeli political party called Mapam, which had in the 1950s “been a communist, Soviet-affiliated faction.” Times of Israel said kibbutz members “had admired Joseph Stalin until his death.” They would, the Times of Israel reports, “celebrate May Day with red flags.”

Mr. Sanders’ kibbutz also spoke of “controlling the means of production, taking from each according to his abilities and giving to each according to his needs.” It might have been, we noted four years ago, that by 1963, when Mr. Sanders was on the kibbutz, he had calmed down. The question abides, though — was the young Mr. Sanders there for the love of Zion or of communism?

And where’s he really at today? Even more importantly, where is his party? It’s astonishing. Remember 2012, when the Democratic chairman had to falsely declare that two thirds of delegates had voiced support for restoring God and Jerusalem planks to the Democratic platform. None of the Democrats on the stages of Carolina, New Hampshire, Iowa, or Nevada has confronted Mr. Sanders on this head.

In the debate last night, Mayor Bloomberg did give a better answer than Mr. Sanders, and so did Senator Warren. Only marginally, though. None of them really confronted Senator Sanders’ Corbynism. No wonder Israel’s foreign minister felt impelled to speak up. The Democratic Party, it seems, has long since decided to leave the issue of Israel to President Trump and the Republicans — and them to embrace it.