DETROIT — Glenn Stevens Jr. can look out his office window in downtown Detroit and see Canada. The view encapsulates historic automobile achievement between two countries despite a flowing river and international border — one that’s on the brink of being ripped apart.

“Our economies in auto between Ontario and Michigan are seamless. They are one and the same,” Stevens, executive director of MichAuto, said Friday. “We don’t even view there being a border, there’s literally a couple of bridges.”