House Oversight Committee Chairman James Comer (R-KY) sent letters Johnson and the mayors for three other major cities – Boston, Denver, and New York – last week, asking them to testify before the committee and hand over all documents and communications related to their city's sanctuary policies.

Mayor Brandon Johnson’s appearance is likely to represent a flashpoint in the ongoing battle with the GOP-controlled U.S House and the Trump administration, which is attempting to strip self-proclaimed sanctuary cities of all federal funding.