“This is the first step towards establishing a public policy about how Mexico should react in the face of a threat,” Armando Ríos Piter, a leftwing senator who introduced the bill, told the Times.
The bill would make it illegal for Mexico to use official cash to fund the building of a border wall. If Trump attempted to seize the $24bn in annual remittances from the US to Mexico to pay for it, the bill would also empower Mexico to retaliate in kind by impounding the same sum, probably through a tax on flows heading in the other direction, says the Times.
Furthermore, if Trump made good on threats to scrap the 1994 Nafta free-trade deal — credited with creating one in three jobs in Mexico — it would call for a review all 75 bilateral treaties between the two countries to establish if they were in the national interests.
That includes the 1848 Treaty of Peace, Friendship, Limits and Settlement that ended the Mexican-American War and transferred a huge swath of Mexican territory to the US, including what is now California, Arizona, New Mexico and Nevada.