CHILMARK, Mass. — President Obama announced Thursday that the United States had canceled longstanding joint military exercises with the Egyptian Army set for next month, using one of his few obvious forms of leverage to rebuke Egypt’s military-backed government for its brutal crackdown on supporters of the ousted president, Mohamed Morsi.

Though the decision is an embarrassment to Egypt’s generals, and will deprive Egypt of much-needed revenue, it lays bare both the Obama administration’s limited options to curb the military’s campaign against Islamists in Egypt and the United States’ role as an increasingly frustrated bystander.

Repeated pleas from administration officials to the generals to change course have gone unheeded, and the United States’ first punitive measure, a Pentagon delay in the delivery of four F-16 fighter jets to the Egyptian Air Force, also had no effect.

Mr. Obama, interrupting his vacation on Martha’s Vineyard to address the violence, struck a now-familiar balance. He expressed outrage at the harrowing scenes this week in Cairo and other cities, while taking pains to preserve the American relationship with the Egyptian armed forces, which are underwritten by the vast bulk of the $1.5 billion a year in military and economic aid.