More difficult is a relative term. More difficult but still easier than other countries so the US remains in a stronger position here. The US can sustain the mess a lot longer than most countries can survive it.

> is a relative term

More "relative" than you think.

Look at the wars the US fought after WWII: Korea, Vietnam, Afghanistan, Iraq, etc. The US suffered a lot less pain than any of those countries and was in a lot stronger position. But those countries were willing to face the pain, the US wasn't. That's why the US lost those wars. The same pattern goes now with Iran. You kill people on those countries, those countries hurt the American voters in their pockets.

In trade wars it might be the same mechanism. For the American people, a trade war is mostly to follow the glorious orange leader. For Canadians it is a matter of national sovereignty.