Yep, US citizens returning from overseas are required to present a US passport, but coming from Canada or Mexico by air, a birth certificate and government photo id does the job for the remainder of this year.
After that there's another year before passports will be required at ground crossings.
At which time the cross-border tourism and shopping will come to a crashing halt in an election year unless an alternative to passports is in place by then.
Don't see many border states voting Republican if it hits the fan as currently designed
