What ails Democrats is an increasingly fanatical demand for ideological "purity" that ultimately eats its own.

“While engaging in marches, meetings, and frenzied propagandizing, Red Guard units attacked and persecuted local party leaders as well as schoolteachers and school officials, other intellectuals, and persons of traditional views. Several hundred thousand people died in the course of these persecutions. … These units soon began fighting among themselves, however, as various factions vied for power amidst each one’s claims that it was the true representative of Maoist thought.” —Encyclopedia Britannica

“I don’t think people in the Beltway are realizing just how toxic the Democratic Party brand is in so many parts of the country.” —Rep. Tim Ryan (D-OH)

Ryan is on to something. But like many of his fellow Democrats, he can’t see the proverbial forest for the trees. What ails Democrats is the same thing that ultimately animated the Communist Chinese government to force its most ardent supporters into exile: an increasingly fanatical demand for ideological “purity” that ultimately eats its own.

Last weekend, Chicago held an LGBT parade called the Dyke March, described by organizers as a “more inclusive, more social justice-oriented” march than the city’s main Gay Pride parade.

How inclusive? Organizers banned the Jewish Star of David flag and removed several people who were carrying it, because the flags “made people feel unsafe,” and the march was “anti-Zionist” and “pro-Palestinian” — rejected marcher and Wider Bridge manager Laurel Grauer told the Windy City Times.

Parade organizers insisted Grauer’s organization, Wider Bridge, was responsible for “provocative actions at other LGBTQ events [and] for using Israel’s supposed ‘LGBTQ tolerance’ to pinkwash the violent occupation of Palestine.”

March participant Ruthie Steiner was perplexed. “With all the people that so hate the LGBTQ community, for it to tear itself apart in self-hatred makes no sense at all,” she said.

Ms. Steiner hasn’t been paying attention. At the 2012 Democratic National Convention, the effort to re-insert references to God and Jerusalem as the capital of Israel back into the party platform, after eliminating both in 2008, was met with a hearty chorus of boos. A clearly embarrassed convention chairman, former Los Angeles Mayor Antonio Villaraigosa, precipitated three voice votes, hoping the yeas would ultimately prevail. When they didn’t, Villaraigosa simply asserted two-thirds of those present approved the measures. Another chorus of boos followed his proclamation.

Moreover, the LGBT community is hardly an anti-Semitic outlier. “The Black Lives Matter movement blindsided its Jewish supporters with the recent unveiling of its social and political policy agenda, a far-left manifesto that strays well beyond police brutality and accuses Israel of ‘genocide’ and ‘apartheid,’” the Washington Times reported last August.

Why they were blindsided in 2016 remains a mystery. “Ferguson, they say, is Palestine,” Haaretz reported — in August of 2014 — about a BLM/Palestinian alliance borne of the riots precipitated by the death of Michael Brown in Ferguson, and its comparison to the “ethnic cleansing” and “war crimes” precipitated by Israel during their 2014 war against Hamas.

A year later, the Washington Post confirmed the growing solidarity between the groups, citing a video with “dozens of #BlackLivesMatter and Palestinian activists delivering a joint message. ‘When I see them, I see us,’” the paper reported.

Perhaps progressive Jewish Americans can take heart in the fact they’re not the only group of leftists who lack sufficient purity. “Every Democrat, like every American, should support a woman’s right to make her own choices about her body and her health. That is not negotiable and should not change city by city or state by state,” declared DNC chief Tom Perez in April. Pro-life Democrat and Louisiana Gov. John Bel Edwards criticized the assertion, insisting, “It’s hard to remain a big-tent party if you have a very small platform.”

It’s even harder when a party’s instincts are inclined toward tyranny. In New York City, the Commission on Human Rights declared the “refusal to use a transgender employee’s preferred name, pronoun, or title may constitute unlawful gender-based harassment.” Or, as UCLA School of Law professor Eugene Volokh aptly explains, “People can basically force us — on pain of massive legal liability — to say what they want us to say, whether or not we want to endorse the political message associated with that term, and whether or not we think it’s a lie.”

Thus in the Big Apple, those who fail to employ pronouns such as “ze” or “hir” can be fined as much as $250,000.

Snopes assures us that assertion is an effort by conservative news organizations to “mislead” the public, because only one “who intentionally and repeatedly refuses to use an individual’s preferred pronoun would be subject to fines.”

In other words, as long as one eventually gets one’s “mind right,” all will be well.

Or will it? On June 15, the Canadian Senate passed Bill C-16 by a vote of 67-11, making the refusal to use transgender pronouns a prosecutable hate crime. No doubt many American leftists who target Christian bakeries refusing to embrace same-sex marriage would like similar legislation passed in America.

Nor are such demands for purity confined to transgenderism. In Britain, Nigel Pelham was sentenced to 20 months in prison, forced to pay a £100 “victim surcharge,” and had two hard drives and a computer confiscated for making disparaging comments about Muslims. Sussex Police Hate Crime Sergeant Peter Allan praised the decision, and encouraged his fellow citizens to turn in anyone else using social media “to spread messages of fear and hate.”

Thus, Britain has criminalized anything government defines as “Islamophobic.”

America? “Now obviously this is a country that is based on free speech, but when it edges towards violence, when we see the potential for someone lifting that mantle of anti-Muslim rhetoric — or, as we saw after 9/11, violence directed at individuals who may not even be Muslims but perceived to be Muslims, and they will suffer just as much — when we see that we will take action,” declared former Attorney General Loretta Lynch —the day after 14 people were slaughtered by Islamists in San Bernardino.

In 1949, a prescient George Orwell foresaw the ethos far too many Democrats currently embrace. “Power is in tearing human minds to pieces and putting them together again in new shapes of your own choosing,” he wrote.

It’s not working on everyone. Millions of decent Americans reject a progressive movement determined to use government, academia, popular culture and the media to “re-shape” their thinking.

That is the essence of toxicity, courtesy of those also determined to make Donald Trump the second coming of Emmanuel Goldstein, with the requisite “Two Minutes Hate” that passes for news at media outlets “setting a new standard for unfavorable press coverage of a president,” according to a Harvard study.

As historian Victor Davis Hanson explains, “Bill Clinton’s formerly competitive Democratic party aged and then evaporated. It was replaced by a hard-left coastal coalition, a pyramidal party — ethnic-identity groups at the base and wealthy elites on top, all united by a mutual disdain for the half of the population that covers 85 percent of the geography.”

That’s exactly what unreasonable demands for ideological purity ultimately engender. And how a party of warring tribes united only by contempt for “the other” survives is anyone’s guess.