Grijalva has promised to provide the final necessary signature on the bipartisan petition to release the so-called Epstein files, which some Democrats—including Jeffries, Rep. Jamie Raskin of Maryland, and Grijalva herself—have claimed is the reason Johnson did not swear her in earlier.

More than 1,000 Starbucks unionized baristas launched an open-ended strike on Thursday, intensifying their push for a collective bargaining agreement over pay and other benefits at the coffee giant.

The seating of Ms. Grijalva brings an end to a weekslong delay that she and other Democrats said was intended to prevent her signature on the Epstein petition.