MCALLEN, Texas — The sleepy-looking downtown of McAllen would give passersby no reason to believe it is the epicenter of a border surge that threatens to consume the Biden administration’s first months.

A large converted nightclub space with blacked-out windows has been transformed into a resting spot for migrant families, 600 of which are released to the Catholic Charities organization every day. An armed security guard stands at the front doors, which are locked for the safety of the masses inside.