It’s possible to make a rational, although not necessarily persuasive, argument that those conservatives who are unreconciled to the notion that the Republican Party now belongs to Donald Trump are wrong. It’s also possible to view the policies of the Obama administration and their possible continuation under Hillary Clinton as dangerous to Israel. It’s also easy to dismiss the efforts of some of those conservatives to conjure up a third party alternative to Trump and Hillary Clinton out of thin air this late in the election cycle as a foolish waste of time that can’t possibly succeed.

But it is not possible to view David Horowitz’s hit piece against Weekly Standard publisher William Kristol published yesterday by Breibart.com under the headline of “Republican Spoiler, Renegade Jew,” as anything but an utter disgrace that sullies the name of the founder of that once estimable site and helps further discredit the pro-Trump camp for which Breitbart.com now serves as a mouthpiece. It also shows once again that, when it comes to the author of this piece, you can take the boy out of the Bolsheviks but you can’t take the Bolshevik out of the boy.

Kristol is the public face of those working to come up with a third party alternative. Count me among those that think those efforts are futile even if I understand why he, and others who support the idea, long to have someone to vote for in November other than Clinton and Trump. Moreover, the notion that anyone associated with this effort thought Mark Cuban, another bad boy billionaire reality television star, was a palatable alternative to Trump, strikes me as mad. But none of that could possibly justify an article that reads like a Stalinist denunciation of a Trotskyite dissident, including the use of a headline that seems to accuse Kristol of being a traitor to the Jewish people and/or Israel.

Horowitz is the author of the justly acclaimed memoir Radical Son that explored his personal journal from the far-left to the ranks of conservatives and a host of other polemics. He is the poster child for those “second thoughts” left-wingers who rejected the politics of the left after the excesses of the 1960s and his contributions to the critique of the radical left were strengthened by the fact that he was once an editor at Ramparts magazine. That Horowitz might be attracted to Trump doesn’t surprise me because he has been an exponent of applying the vicious tactics of the left that he grew up with on behalf of the right. Like many who like Trump because he is gutter fighter with no scruples when it comes to fighting dirty, the man who helped launched the “slap Hillary” game on the Internet not only on the side of the billionaire but is ready, like the candidate, to say just about anything to discredit an opponent.

That is the only way to understand why Horowitz would write and Breitbart.com would publish the “Renegade Jew” smear of Kristol.

Horowitz’s defense of Trump shouldn’t detain us long. We know that many Trump supporters like the candidate precisely because he is a vulgar braggart who can defy political correctness with impunity, even if many of them know that a lot of what he says is self-contradictory nonsense. Many other Republicans are now getting behind him because they view American politics as a binary choice in which the person running under the Republican label is always preferable to any Democrat. But Horowitz goes further and claims than either of those positions and proclaims Kristol’s critique of Trump’s bad character to be at fault. In doing so, he actually defends former boxing champion and convicted rapist Mike Tyson. The notion that Tyson is a symbol of repentance, or “an icon to an important segment of the voting population” is risible and so foolish as to not even be worth the space it would take to fully debunk it.

Even worse, Horowitz actually claims that Kristol is wrong to assert that Trump is a “crackpot conspiracy theorist.” In making such an unsupportable argument, Horowitz conveniently fails to mention that Trump was the nation’s number one birther when it came to Barack Obama. Nor does he take into account that Trump has given his support to the left’s canards about George W. Bush knowingly lying the nation into the war in Iraq. But he doesn’t hesitate to rationalize and even endorse Trump’s despicable effort to spread the notion that Ted Cruz’s father was associated with Lee Harvey Oswald, the man who assassinated John F. Kennedy, a smear that originated in the Trump-friendly National Enquirer fabulist tabloid. According to Horowitz, lies like that are okay because they are merely “dirty tricks” intended “to throw a rival off balance and gain an advantage.” Which is to say that it is okay to lie, and to even spread a conspiracy theory. If such a stance seems incompatible with any notion of the requirements of a citizen in a constitutional republic or of conservative ethics and values, so much the worse for ethics and values. For old Marxists, the ends always justify the means even if it requires you to justify gobsmackingly stupid canards or threats against an opponent’s wife.

As for policy, Horowitz further embarrasses himself by defending Trump’s vapid and inconsistent “America First’ foreign policy. That Trump’s isolationism and his attraction to authoritarians like Vladimir Putin are antithetical to the conservative effort to promote a strong America that Horowitz has spent the last few decades supporting ought to be obvious even to the readers of Breitbart. Indeed, Trump makes no bones about not being a conservative and mimicking the far left critique of conservative foreign policy. On that, as on many domestic issues, Trump is closer to the left than he is to any recognizably conservative position. But to a polemicist like Horowitz who has always — whether on the left or the right — eschewed nuance, any deviation from the current Trump party line must be stamped out with fervor and total destruction of not only the position but also the character of the opponent.

But the real offense here is not Horowitz’s laughable defense of Trump’s behavior or his vapid policy positions. It’s his attempt to wrap him in the Star of David and to somehow brand his opponents as traitors to the pro-Israel cause that should trouble everyone including those that believe Trump is the lesser of two evils in 2016.

Horowitz is right to label the Iran nuclear deal as a threat to Israel as well as to the West. It was one of the seminal issues of the last four years and one on which Trump was notably silent until he started running for president. If he is elected, perhaps it will be one topic on which he won’t be as “unpredictable” as he promises to be on most issues. If so, that would be good for both Israel and the United States.

The deal didn’t happen on Hillary Clinton’s watch at the State Department and might never have occurred without her being replaced by John Kerry, but she still should be judged for being one of its supporters. On this point, as with Israel’s conflict with the Palestinians, we know what we would be getting with Clinton. She is less willing to bash Israel than President Obama or Bernie Sanders, but the person who served as the “designated yeller” at Prime Minister Netanyahu can’t be counted among its reliable defenders.

By contrast, Trump is a mystery. He claims at times to be a fervent supporter of Israel especially when he reads from scripts. But at other times, his deal-making hubris makes him sound as if he might repeat the folly of Obama and Kerry while proclaiming himself to be “neutral” between Israel and the Palestinians. His isolationist tendencies must also trouble supporters of Israel since an American retreat from the Middle East (other than a war against ISIS that Trump claims he will fight without intervening in the region) will weaken the Jewish state and strengthen foes like Iran.The Republican Party has become a bedrock supporter of Israel in recent decades while many Democrats — especially their liberal base — have drifted away from that position. But the nomination of an isolationist like Trump has undermined the thesis that the two parties are so different on foreign policy.

Again, it is possible to argue from these facts, as some ardent members of the pro-Israel community have done, that Trump is the better choice from the point of view of strengthening the U.S.-Israel alliance. But it is not possible to conclude that someone who believes Trump can’t be counted on or viewed as much of an improvement over Clinton is a traitor to Israel. It is certainly not possible to say that to Kristol, who has devoted so much effort to support of Israel throughout his career and especially as a leader of the opposition to Obama’s policies.

In the last two decades, Horowitz’s publishing and activist projects have prioritized support for Israel, which is why his confession in the last paragraph of his piece that he has never visited the Jewish state is puzzling. But even if his concern for Israel should be considered both sincere and heartfelt that doesn’t justify his use of Stalinist dialectical tactics to smear Kristol.

Neither Horowitz nor Breitbart.com have the right to assume the pose of a Jewish pope with the right to excommunicate all those who cannot stomach Trump as heretics. Indeed, his invocation of “America First” and the use of a term like “renegade Jew” in the headline (though not in the text of the article) seems to echo the smears of the pro-Trump alt right racists who have attacked conservative critics of the candidate with an avalanche of anti-Semitic invective. Such tactics may be standard operating procedure on the far-left, but they have no place in the conservative movement even in the Donald Trump era. While Horowitz has exhibited the sort of blind partisan loyalty required by Trumpites, with this article he has discredited himself — and Breitbart.com — in the pro-Israel community and among fair-minded conservatives.