What you need to know:
- The change in the dress code came as a surprise and has been dubbed the "Fetterman rule" due to Democrat Pennsylvania Senator John Fetterman's penchant for casual wear in the Capitol.
Critics warn decorum is falling apart at the seams in the US Senate after the Democratic leadership changed the rules to end the old requirement on wearing a jacket and tie in the tradition-bound chamber.
Majority Leader Chuck Schumer told the Senate Sergeant at Arms that the chamber's unwritten dress code need no longer be enforced.
The relaxed attire rule applies to all of the chamber's lawmakers, but the switch was seen as a special deal for Democratic Senator John Fetterman, whose love of shorts and hoodies has turned dress-down Friday into dress-down every day.
Fetterman's dress style, or perhaps lack of style, became his signature on the campaign trail before entering the Senate this year. He also gained sympathy from many after he had to undergo treatment for clinical depression soon after taking office.
Schumer said senators will be able to wear what they want, even if "I will continue to wear a suit."
But the new rules, first reported by Axios, were met with mockery on the right.
Republican Susan Collins joked to NBC that she planned to "wear a bikini."
"I think there is a certain dignity that we should be maintaining in the Senate, and to do away with the dress code, to me, debases the institution," she said.
Senator Bill Hagerty, a Republican, told Fox Business that the move was "just another step in the movement by the Democrats to transform America, to take us to a place that is much less respectful than we historically have been."
Lawmakers dropping in to vote in gym clothes or other unusual attire had previously been able to circumvent the rules by keeping one foot in the adjacent cloakroom, according to US media.
Fetterman said he may "dress like a slob," but the sartorial sniping meant "the right have been losing their mind."
Both the House and Senate have in recent years relaxed rules to allow women to wear sleeveless dresses. And in 2019, the House green-lighted religious headwear to allow for the hijab worn by Representative Ilhan Omar.