Senator Chuck Schumer, the majority leader, will no longer enforce the informal dress code for the chamber, which for decades has dictated that members wear business attire.
In the tradition-bound halls of the Senate, customs die hard and rules can be next to impossible to change. But on Monday, with a potential government shutdown days away, a newly begun impeachment inquiry and lawmakers preparing for a visit this week from the president of Ukraine, a major change had the Capitol abuzz.
For the first time in centuries, lawmakers are no longer expected to suit up to conduct business on the Senate floor.
Senator Chuck Schumer, Democrat of New York and the majority leader, has established a new dress code — or rather, done away with the old one — allowing members to take a more business-casual approach to their workwear.
The change, reported earlier by Axios, involved directing the Senate’s sergeant-at-arms — whose job, aside from directing security in the chamber, also entails enforcing outfit standards for all who enter it — that the previous policy that all senators must be clad in business attire when on the floor is no longer to be enforced.
“There has been an informal dress code that was enforced,” Mr. Schumer said in a statement. “Senators are able to choose what they wear on the Senate floor. I will continue to wear a suit.”
The modification is in many ways a bow to reality: In recent years, there have been plenty of senators who have departed from the suit-and-tie uniform that for decades was considered the only acceptable attire. It most clearly reflects the influence of Senator John Fetterman, the 6-foot-8, tattooed, first-term Democrat from Pennsylvania. After briefly donning a suit and tie for his first few months in Congress, he has recently reverted to wearing his signature Carhartt sweatshirts and baggy shorts.
As is the case with any sartorial change in Washington — be it footwear, dress color, suit shade or wigs — the announcement has generated a big reaction.
Right-wing Republicans, including some who have routinely shattered norms of decorum and conduct on Capitol Hill, professed outrage.
Representative Marjorie Taylor Greene, the hard-right Republican from Georgia who rose in the House chamber during President Biden’s State of the Union address in February to scream “Liar!” called the clothing policy change “disgraceful.”
“Dress code is one of society’s standards that set etiquette and respect for our institutions,” she wrote on X, the social media platform formerly known as Twitter.
(In apparent response, Mr. Fetterman referred in his own post to a hearing where Ms. Greene showed sexually explicit images of Hunter Biden, a break from Capitol Hill etiquette if ever there was one. Other Democrats called it ironic for Ms. Greene, who has openly sympathized with the rioters who attacked Congress on Jan. 6, 2021, to be lecturing about good manners at the Capitol.)
Senator Mike Lee, Republican of Utah, was also disdainful of the change in rules. “It’s just not that hard to wear a jacket and tie,” he wrote on social media, adding that, “pants are a must — not optional.”
Unlike most rules that govern the Senate, there is no official, written dress code. But by custom, senators have for decades been informally required to wear business attire: typically suit and tie for men and dresses with covered shoulders or pantsuits for women.
The most recent adjustment came in 2019, after Senator Amy Klobuchar of Minnesota, then the top Democrat on the Rules Committee, successfully pushed leaders to allow women to wear sleeveless dresses, a change the House had adopted several years earlier.
The House also modified its rules of dress in 2019 to allow religious headgear to be worn on the floor for the first time, to accommodate Representative Ilhan Omar, Democrat of Minnesota and one of the first two Muslim women elected to Congress, who wears a hijab.
In the Senate, the only workaround to the dress code has been an exception made for votes, when senators are allowed to place one foot on the floor from an adjacent cloakroom and signal “yea” or “nay” without fully entering the chamber.
But Mr. Fetterman is not the only flouter of tradition. Over the past several years, the outfit choices of senators — like much of white-collar, post-pandemic America — have become more laid-back and occasionally more defiant.
Senator Ted Cruz, Republican of Texas, turned heads when he showed up to vote in sweaty athletic gear. When asked about his sneakers and shorts, he quipped to reporters that votes were scheduled in the middle of his basketball game.
No stranger to statement-making fashion choices, Senator Kyrsten Sinema has sported pastel-colored wigs to cast votes and turned heads in 2021 when she presided over the Senate in a denim vest and black T-shirt.
When Richard Burr of North Carolina retired this year after three terms in the Senate, he took with him a collection of socks that people had given him over the years. Mr. Burr, a Republican, was known for his sockless footwear choices, once posting on social media that he had “99 problems but socks ain’t one.”
He could sometimes be spotted around the Capitol sporting a polo shirt and shorts and a pair of flip-flops, with a navy blue blazer thrown on top as his only nod to the dress code.