Denver Mayor Mike Johnston on Wednesday agreed to testify before Congress over Denver's status as a sanctuary city. Why it matters: Johnson will be pressed to defend Denver's policies protecting migrants from deportation at a time when the U.

Denver Mayor Mike Johnston on Wednesday announced he would attend a congressional hearing for an investigation into so-called sanctuary cities.

Denver Mayor Mike Johnston has decided to testify before a congressional committee next month after its members asked him to travel to Washington, D.C., to explain the city’s policies limiting cooperation with federal immigration authorities.