Bernie Sanders won’t be speaking at the annual American Israel Political Action Committee Conference. The four other candidates still in the presidential race—his Democratic rival Hillary Clinton and Republicans Donald Trump, Ted Cruz, and John Kasich—will all be speaking.

Earlier this week, a petition made the rounds among progressives urging Sanders not to speak at the convention, based on criticisms that AIPAC is too supportive of controversial policies held by Israeli Prime Minister Benjamin Netanyahu. Sanders’ political base is in the progressive wing of the U.S., and some of his supporters wanted him to avoid the gathering on political grounds.

Sanders was more diplomatic, issuing a letter to AIPAC President Robert Cohen saying that while he would have liked to speak at the event, he had previous commitments “in the West.”

Since AIPAC has chosen not to permit candidates to address the conference remotely, the best that I can do is to send you a copy of the remarks that I would have given if I was able to attend. We should be able to get that speech to you on Monday. Any help that you could give us in getting those remarks out to your members would be much appreciated.
The contents of the speech-that-wasn’t will still be hotly anticipated; if Sanders chooses to maintain the general Democratic line of supporting Israel and the eventual development of a Palestinian State, he may satisfy some of his more centrist supporters. If he stands against Israel’s occupation of the West Bank and other controversial policies, he could solidify his credentials among some progressives.