Dhaka, June 17 -- Within about eight hours, President Donald Trump shifted from suggesting a nuclear deal with Iran was still "achievable" to urging the 9.5 million residents of Tehran to evacuate for their safety. He cut short his trip to the G7 summit to return to Washington for urgent discussions with his national security team.

Trump arrived at the White House at a pivotal moment in his presidency. After five days of missile strikes, Israel has inflicted significant damage on Iran and believes it can now deliver a permanent blow to Tehran's nuclear program-especially if it receives additional support from the Republican president.

However, deeper U.S. involvement, possibly including supplying Israel with bunker-buster bombs capable ...