Five former U.S. ambassadors to Israel have said Donald Trump’s choice of envoy is “unqualified for the position,” in an unprecedented diplomatic slap.

The group – a mix of Democratic and Republican presidential choices spanning three decades – joined forces this week in a letter to the Senate Foreign Relations Committee, expressing “concern” about David Friedman, a bankruptcy lawyer who supports settlements.

Friedman has no diplomatic or political experience, but helped bail out Trump’s businesses. He funds Jewish settlements in the West Bank and has said American Jews who support the establishment of a Palestinian state are “worse than kapos”, in reference to Jews who turned in other Jews in Nazi death camps. He also said President Obama and John Kerry were “anti-Semitic” and described the Anti-Defamation League (ADL) as “morons”.

Among the five former ambassadors is Thomas Pickering, an influential figure who has been at the heart of U.S. national security and foreign policy decision making since working with Richard Nixon and Henry Kissinger in the 1970s.

In the letter, they say Friedman holds “extreme, radical positions” and thinks the two-state solution is an “illusory solution to a non-existent problem”. They questioned his “balance and the temperament,” saying an ambassador “must be dedicated to advancing our country’s longstanding bipartisan goals in the region”.

They added: “If Israel is to carry on as a Jewish, democratic nation, respected internationally, we see no alternative to a two-state solution… We are concerned that Mr Friedman strongly disagrees.” They asked the Committee to carefully evaluate his appointment, saying: “We believe [Friedman] to be unqualified for the position.”