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. ■

U.S. President Donald Trump's administration has directed prosecutors to investigate officials who resist immigration enforcement efforts, intensifying a sweeping crackdown that Trump launched the day he took office.

State and local leaders across the country are bracing for a tidal wave of aggressive immigration policies and possible mass deportations that President Donald Trump has vowed to enact in the hours and days following his inauguration Monday.