Forty years ago, Iranian students took 66 Americans hostage at the U.S. Embassy in Tehran, launching the hostage crisis that would grip the United States for 444 days. As chants of “Death to America” consumed the new Islamic republic, the United States found an unlikely ally in navigating the tumultuous political changes and securing the release of the first batch of hostages on Thanksgiving Day, Nov. 20, 1979: the Palestine Liberation Organization.

The PLO hoped its efforts to secure the release of these 13 hostages would open a conversation with the United States in the broader Arab-Israeli arena. But it would take almost another decade, a bloody Lebanese civil war, a PLO exile in Tunisia and a total PLO acceptance of U.S. requirements before the United States finally opened direct communications with the Palestinian leadership, in 1988. Those contacts enabled the Israeli-Palestinian peace process of the 1990s. That controversial and hard-fought diplomatic ground, however, is under threat from the Trump administration.

When the Iranian revolution broke out in 1979, the Carter administration had just finalized a peace treaty between Israel and Egypt and was working toward some form of Palestinian solution. While more sympathetic toward the Palestinians than his predecessors, President Jimmy Carter refused to talk to the PLO directly. The group was considered too radical because of its use of violence, its refusal to recognize Israel and its unwillingness to accept U.N. Security Council Resolution 242, which was the foundation for the “land for peace” formula. Moreover, the United States was also bound by a secret pledge to Israel that there could be no negotiations with the PLO until the organization recognized Israel’s right to exist.

While Carter spent time and energy trying out creative ways of establishing contacts with the PLO during his first year in office, the divide was too deep. However, when the Americans were taken hostage in Iran on Nov. 4, 1979, the Carter administration quickly reached out to the PLO in Lebanon, hoping the organization could act as a go-between to get Iran to release the hostages.