U.S. President Joe Biden effectively gave Israeli Prime Minister Benjamin Netanyahu an ultimatum: protect Palestinian civilians and foreign aid workers in Gaza or Washington could rein in support for Israel in its war against Hamas militants. The message, after months of U.S. calls for Israel to change its military tactics that have killed tens of thousands of Palestinians, followed an Israeli attack that killed seven World Central Kitchen (WCK) aid workers and triggered global outrage. Israel admits the strike was a mistake. The White House did not say exactly what steps it wanted Netanyahu to take, nor what it would do if…