the enemy of my enemy is my friend

According to the Wall Street Journal, Israel and Egypt colluded over Gaza,leaving the United States on the sidelines.

The U.S. encouraged Israel and Egypt to forge a close security partnership. What Washington never anticipated was that the two countries would come to trust each other more than the Americans, who would watch events in Gaza unfold largely from the sidelines as the Israelis and the Egyptians planned out their next steps. 

          The Journal report details growing Israeli-Egyptian cooperation under President Sisi driven by a shared antipathy toward Gaza-ruling Hamas.

U.S. officials, who tried to intervene in the initial days after the conflict broke out on July 8 to try to find a negotiated solution, soon realized that Mr. Netanyahu's office wanted to run the show with Egypt and to keep the Americans at a distance, according to U.S., European and Israeli officials.

The Americans, in turn, felt betrayed by what they saw as a series of "mean spirited" leaks, which they interpreted as a message from Mr. Netanyahu that U.S. involvement was neither welcomed nor needed.

       Israel also gained goodwill with Egypt by using its political clout in Washington to win resumed aid to Egypt, despite a U.S. law requiring a cutoff in the event of a military coup.

         While this is a good example of realpolitik in operation, it makes it even harder for the U.S. to provide a leadership role in the conflict.