"I thought there was a better way to expedite the legal flow of traffic and people," he said.
"If people have to have a passport, it's going to disrupt the honest flow of traffic. I think there's some flexibility in the law, and that's what we're checking out right now," the president said.
As I said before in summary, his goal is to expedite the flow of traffic across the border.
No decision has been made, and they're also not starting from scratch. Your argument would carry much more weight with me were this just beginning. Then I'd say, sure, one standardized document sounds best. But all these other systems have been in place for years. Removing/replacing them willy nilly will likely do more to impede border traffic than we can imagine.