Any final decision would await the return of President Trump from Europe. He has threatened to use emergency powers to impose the tariffs — an atypical use of the law that goes beyond his predecessors.

Details: The arrangement being discussed would require migrants to seek asylum in the first safe country they enter.

Mexico has pledged to send thousands of troops to the border, if a deal is reached.

Analysis: Diplomats on both sides of the border and immigration experts say that Mexico could step up enforcement at the border and provide more humanitarian relief to migrants, but that completely stemming the flow of migrants would be nearly impossible.

Impact: Consumers across the U.S. would be affected if the tariffs were imposed. These are the states that would be hardest hit.