The key problem with Steve Bannon, Donald Trump's newly appointed chief strategist, isn't that he's an antisemite.
He may be, though the only piece of personal information suggesting antisemitic views comes from a contentious divorce proceeding two decades ago - and such charges need to be viewed sceptically.
Antisemites usually out themselves on a regular basis because they can't help it. And the late Andrew Breitbart, who was his close friend as well as mine and a loyal if entirely non-practising Jew, would not have had a minute's time for someone who spewed antisemitism in private.
No, the key moral problem with Mr Bannon is that as the chief executive of Mr Breitbart's namesake organisation, he is an aider and abettor of foul extremist views, including antisemitic ones.
Mr Bannon used the site to promote the alt-right, which has retailed antisemitism as well as general outright racism and white nationalism. The distinction may seem like a minor one, but it isn't; the hatred Breitbart has channelled is too general for it to be singled out for its antisemitic content.
Breitbart hasn't promoted the alt-right for the purposes of advancing the alt-right agenda, I don't think. It may well be he doesn't care about these matters one way or the other. What he hates are liberalism and leftism, and he sees the alt-right's utterly implacable vileness as a useful organising tool.
He is a self-described Leninist who wants to use Lenin's "by any means necessary" philosophy to extirpate liberalism on the one hand and to pursue the concomitant extirpation of those he perceives as collaborationist conservatives on the other.
That's why the greatest degree of passion on the site these past two years has been directed not at the left but rather at Republicans deemed insufficient in their rage against the left and insufficiently bloodthirsty in their efforts to destroy the left. They are his kulaks.
It should go without saying that the president of the United States should not have a tawdry, destructive, and repulsively uncivilised goon as a chief strategist.
One can hope he will be moved into a tiny windowless office at the end of the hall in the West Wing next to the closet where they keep the toilet paper and scrub brushes. One can hope. One does not know. He could be Mr Trump's Valerie Jarrett (Barack Obama's senior adviser) for all we know.
With Mr Bannon in a senior role at the White House, and the possible appointment of the radical congressman Keith Ellison as head of the Democratic National Committee, we could be seeing our political system devolving to its extremes.
Mr Trump hasn't sounded as though that is the direction in which he is heading himself in the interviews he has given since the election, but it is all a guessing game until he starts implementing actual policy.