Canada already lost their measles elimination status and had several times higher measles rate than the US.
At this point, anyone pushing anti-vaccine thinking as an American problem is just pushing anti-American bias. Vaccine misinformation and hesitancy is an almost worldwide problem.
Thinning this is a US problem completely misunderstands the nature of the misinformation problem.
And I hope there's vaccination requirements for travel, according to how public health officials determine threats.