Machen stands against the boycotting of Israeli universities. He condemned the proposed boycott in a letter that ran as a full-page advertisement in the August 8, 2007 edition of "The New York Times". He helped write the letter in opposition to a recent vote by Britain's leading faculty union, which decided to debate the possibility of boycotting Israeli academic institutions. If passed by Britain's University and College Union, the boycott would cut off relations with Israeli schools to serve as a rebuke of Israel's Palestinian policies.