Pakistan, June 15 -- President Donald Trump has long bet that he can scare allies into submission - a gamble that is increasingly being tested ahead of the Group of Seven summit beginning Monday in Canada.

He's threatened stiff tariffs in the belief that other nations would crumple. He's mused about taking over Canada and Greenland. He's suggested he will not honor NATO's obligations to defend partners under attack. And he's used Oval Office meetings to try to intimidate the leaders of Ukraine and South Africa.

But many world leaders see fewer reasons to be cowed by Trump, even as they recognize the risks if he followed through on his threats. They believe he will ultimately back down - since many of his plans could inflict harm on the ...