Can it be a coincidence that of all the millions of Americans Secretary Clinton could have picked as her running mate, she chose, in Senator Kaine, one of the eight Democrats who boycotted Prime Minister Netanyahu’s address last year to a joint meeting of Congress? Not a chance. It’s one marker of the fact that for all Mrs. Clinton’s protestations of support for the Jewish State, it would be a fool’s wager to count on her when the chips are down.

Mr. Kaine was especially disappointing on this head — offering, in an interview last year with the Jewish Daily Forward, a particularly pusillanimous attempt to justify his boycott of Mr. Netanyahu’s speech. “I’m not dumb,” he dissembled. “I knew not going to the speech might make some folks mad with me — there would be a political price.” He represented that he was standing on principle over procedure.

Then again, too, the Articles of Appeasement that were finally struck between the Democratic administration and the Iranian regime failed to muster support in either the Senate or the House. Majorities in both of them were against the agreement, though in the Senate not enough to bring the matter to the floor. Mr. Kaine was one of the Senators who, in effect, sided with Iran and blocked the deal from going to the floor, where it faced defeat.

If that sounds harsh, mark that the New York Times accused senators and congressmen opposed to the deal of “the unseemly spectacle” of “siding with a foreign leader against their own commander in chief.” The Times meant, siding with Prime Minister Netanyahu. Mr. Obama then took the deal Mr. Kerry struck with the ayatollahs to the United Nations Security Council, where his administration voted to back it against majorities in America’s own Congress.

Mr. Kaine was absolutely no help on any of the Iran deal, which was opposed by both Mr. Netanyahu’s Likud and the leader of the left opposition. He was also one the senators who in 2014 refused to sign a letter to President Obama warning of legislated legal constraints on funding the Palestinian Arab authority after it struck its alliance with Hamas. The letter, led by Senators Susan Collins and Ben Cardin, was signed by 88 senators from both parties.

Senator Kaine was one of the 12 who refused to sign, a reader reminded us when the first edition of this editorial was issued. So it takes some brass for Mrs. Clinton’s new running mate to boast that he is pro-Israel. As the Clintons might say, it depends on what the meaning of “is” is. As for the price Mr. Kaine has supposedly paid for his willingness to boycott Mr. Netanyahu’s speech, he can now count his selection as his party’s vice presidential nominee. What a cost.