The U.S. president faces pushback over the risk of U.S. involvement in the escalating conflict between Israel and Iran.

"The full strength and might of the U.S. Armed Forces will come down on you at levels never seen before," Trump warned.

It’s a tableau no world leader — except perhaps President Donald Trump — wants to repeat. Convening in the Canadian Rockies for this week’s Group of 7 summit, presidents and prime ministers are hoping to avoid the acrimony that pervaded the last time this country played host to the world’s most exclusive club.