This could prove endlessly entertaining:

Mexico threatens to cancel treaty that ceded Texas and California to US if Trump gets elected

The bill Piter is proposing would specifically cancel the 1848 Treaty of Guadalupe Hidalgo, which ended the Mexican-American War and ceded Texas and California as well as parts of Arizona, Colorado, New Mexico, Nevada, Utah and Wyoming to the U.S. if Trump cancels NAFTA.

Like most proposals out of politicians, I assume that this is just grandstanding and useless theater. But boy howdy would it be entertaining to watch Mexico try to reclaim Texas…