The Republican offensive against the judiciary has been unsubtle, but the Trump administration hasn’t gone so far as to arrest a sitting judge — until now.

Federal agents on Friday arrested a US judge for allegedly shielding an undocumented migrant, escalating a struggle between the White House and courts over President Donald Trump's hardline deportation policies.

Judge Hannah Dugan is accused of escorting the man and his lawyer out of her courtroom through the jury door last week after learning that immigration authorities were seeking his arrest.