Representatives of Mr. Morsi have declined repeated requests over more than three days for comment on his remarks. One reason may be that the re-emergence of his previous statements has now trapped him in a political bind. While his past comments may be a liability abroad, he faces a political culture at home in which such defamation of Jews is almost standard stump discourse. Any attempt to retract, or even clarify, his slurs would expose him to political attacks by opponents who already accuse him of softness toward the United States and Israel.

Signs asserting Mr. Morsi works for Mr. Obama are already common at street protests. Perhaps “the Muslim Brotherhood is so desperate for U.S. support that it is willing to bend over backwards to humor the Israelis,” Emad Gad, a leader of the Social Democratic Party, suggested in a recent column.

Outlining Mr. Morsi’s dilemma, the Egyptian satirist Bassem Youssef used the president’s anti-Semitic remarks to set up a contrast with his more recent collaborations with Washington and Israel, including the brokering of a cease-fire with Palestinian militants in Gaza. Mr. Youssef, whose television program broadcast the video clip about hatred Friday night, juxtaposed Mr. Morsi’s 2010 statements denouncing “Zionists” and their Western supporters, including Mr. Obama, with the Egyptian president’s more recent declaration that he hoped Egypt and the United States could be “real friends.”

“Of course being in an international role has its rules and restrictions,” Mr. Youssef said on the program, advising Mr. Morsi and his Islamist allies to retract their inflammatory talk: “Admit everything you said in the past was a joke, or stop bluffing.”