Saturday is International Holocaust Remembrance Day. For President Trump, it is a shot at redemption.

He failed a moral test on the same occasion a year ago when he issued a message that strangely left out any specific reference to the six million Jews murdered in the Nazis’ industrialized genocide. The White House cast the omission as somehow an “inclusive” approach because, it said, Roma, gays, the disabled and others were also victims. But Jews were unique targets. Failing to mention them was as bizarre as it would be to write a history of slavery and ignore the ordeal of Africans brought to America in chains.

It was an example of Mr. Trump’s complex, at times disturbing, instincts in regard to Jews.

On one hand, his elder daughter is a convert to Judaism, married to an observant Jew. His years in New York real estate involved frequent dealings with Jewish counterparts. He has thrilled many American Jews by recognizing Jerusalem as Israel’s capital (though he’s displeased many more of them, who fear that this will impede the search for Middle East peace). At a ceremony on Capitol Hill in April, he spoke forcefully about the Holocaust as he pledged “never again.”

But there’s always another hand with Mr. Trump, and it can be unsightly.

After a march that included neo-Nazis in Charlottesville, Va., last summer, the president said that there were “very fine people” among them. No, there weren’t. There are no very fine Nazis, neo or otherwise. He has passed along tweets from unabashedly anti-Semitic accounts, and has been slow to denounce assaults, vandalism and other Jew-hating acts, which the Anti-Defamation League says have risen sharply. In the first nine months of 2017, the latest period with available numbers, the league reported there were 1,299 such episodes, an increase of 67 percent over the 779 recorded in the same stretch of 2016.