What role did Governor Shapiro’s Jewishness have in his not being selected as Vice President Harris’s running mate? We will never know the answer with certainty, because we do not have access to the workings of Ms. Harris’s mind. On paper, though, it seems clear to many that Mr. Shapiro was the obvious choice to help Ms. Harris’s electoral prospects.

He is, after all, the popular governor of the most important state on the electoral map for Democrats. He is more to the center than Ms. Harris, thus expanding her base and potentially attracting more independents and moderates. Many knowledgeable observers think that if Mr. Shapiro’s name had been, say, Jim Shepard instead of Josh Shapiro he would’ve been selected.

Yet woke progressives mounted a campaign against him, focusing on his Zionism, his support for Israel, and his opposition to some of the post October 7 protests.  In these respects he was no different than the other potential candidates, including Governor  Walz. Indeed, in an effort to placate the anti-Israel progressives, Mr. Shapiro went out of his way to exaggerate his criticism of Prime Minister Netanyahu, calling him “one of the worst leaders of all time.”

No reasonable critic of Mr. Netanyahu would categorize him with past leaders such as Stalin, Castro, and Arafat. Mr. Shapiro also seemed to apologize for his teenage activities on behalf of Israel, claiming that he was young. None of these attempts to pander to the hard left have worked

Some defenders of Ms. Harris’s selection argue that it was about the Chicago convention, at which anti-Israel protests are expected. They believe that this problem would have been exacerbated by the selection of the Jewish vice-presidential candidate and that the selection of Mr. Walz will help mute these protests.

Whatever the precise reason or reasons, the rejection of Mr. Shapiro was a victory for the anti-Israel and often anti-Jewish elements of the progressive left of the Democratic Party. It was a defeat for moderates who hoped to broaden Ms. Harris’s base of support.

In that respect it was the mirror image of what many people believe is President Trump’s mistake in selecting Senator Vance to be his running mate instead of selecting someone closer to the center who might attract moderates who voted for Governor Haley, Trump doubled down on his attempt to appeal to right-wing elements within the republican party. The likelihood that this choice may hurt him in the general election didn’t seem to influence Trump.

Both presidential candidates have selected running mates that move them away from the center and closer to the more extreme elements of their parties. The big losers are the vast majority of Americans who are moderate and who support centrist policies.

The difference is the feeling among Democratic moderates that Mr. Shapiro’s religion may have played a role in his rejection. For some that would be a determining factor: they could not vote for a presidential candidate who gave in to the bigotry of woke progressives who simply didn’t want to see a Jewish Zionist on the ticket. For those who suspect — but can’t be certain — that Mr. Shapiro’s religious affiliation may have played a disqualifying role in his rejection, the issue is more cloudy but still a concern.

There can be, in any event, absolutely no doubt that there are elements within the progressive left of the Democratic Party that did not want Mr. Shapiro to be the nominee precisely because he is perceived to be a Jewish Zionist. Some of these progressives are simply Jew haters. Others are Israel haters. They lobbied hard against Mr. Shapiro and are now celebrating a victory of bigotry over principle.

There can also be no doubt that these bigots had some influence in the decision to reject Mr. Shapiro. Precisely how much and what kind of influence they had is subject to debate. What is also subject to debate is how unbigoted Democrats should evaluate the complexities that went into the decision to reject Mr. Shapiro.

It was a decision to reject Mr. Shapiro. Mr. Walz was selected, at least in part, because he is not Mr. Shapiro. He may be a good candidate, and he appears to be a decent man. Yet he would not have stood a chance against a non-Jewish, equally popular governor of Pennsylvania. That is the sad reality that decent voters now have to face.