Sen. Bernie Sanders speaks at a campaign rally in Phoenix. He is the only presidential candidate who will not appear at the convention of the American Israel Public Affairs Committee. (Ricardo Arduengo/AP)

Sen. Bernie Sanders has notified the American Israel Public Affairs Committee, a leading pro-Israel lobbying group, that he will not attend its annual conference next week, the only presidential hopeful from either party to be a no-show.

In a letter sent Friday to AIPAC President Roger Cohen, the senator from Vermont and the only Jewish candidate in the race said he would be campaigning in the western half of the country, and “the campaign schedule that we have prevents me from attending.”

His primary Democratic opponent, Hillary Clinton, is scheduled to address the group Monday. The three remaining Republican candidates — Donald Trump, Sen. Ted Cruz (Tex.) and Ohio Gov. John Kasich — are all slated to speak later in the day.

Sanders expressed regret, saying that he would have enjoyed the chance to speak at AIPAC.

“Obviously, issues impacting Israel and the Middle East are of the utmost importance to me, to our country and to the world,” he wrote Cohen.

Sanders offered to send a copy of the speech he would have made had he attended, citing AIPAC’s decision not to allow candidates to address the conference remotely, and ended on a breezy note: “Thanks very much. Hope the conference goes well.”

AIPAC’s annual convention always attracts an A-list array of politicians. Vice President Biden will speak at the opening of the multi-day conference, and House Speaker Paul D. Ryan (R-Wis.) will appear alongside the GOP candidates.

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Israeli Prime Minister Benjamin Netanyahu, who also canceled an appearance before AIPAC and a meeting with President Obama, is expected to appear live via satellite.