‘Poor Mexico, so far from God and so close to the United States.’ This lament by late nineteenth-century Mexican strongman Porfirio Díaz is often cited to characterise the nation’s deep mistrust, paranoia, and envy of the colossus to the north. For much of their 200-year-long relationship, this pessimistic outlook was often justified. The nearly 25-year-old North American Free Trade Agreement (NAFTA) – a US$1.4 trillion trade pact supporting as many as 14 million jobs in Canada, Mexico and the United States, signed into US law by then president Bill Clinton in December 1993 – has done a great deal to allay Mexico’s distrust of the United States. But as US President Donald Trump seeks to overhaul and perhaps tear up the agreement, it has returned and is poised to intensify. While at this point mostly hypothetical, ruptures over NAFTA could fracture the robust security and defence cooperation that currently exists between Mexico and the US.