A co-op of ethnic German Hutterite farmers, who arrived in the 19th century, own the Dakota Provisions plant. But migrants from Venezuela, Thailand and other countries, earning around $14 per hour, perform the dangerous, back-breaking work.

This is where Mr Trump’s talk of an “invasion” becomes more than rhetorical bombast. Framing the cartels as terrorists invading America is meant to legitimise his use of the law. And because America is being invaded, Mr Trump argues, he can block anyone from crossing the border. The courts may not see it that way. ■

"My office is a law enforcement entity. We are going to follow the Constitution and uphold the law," Krasner said as Trump officials threatened consequences for uncooperative local officials.