“It just creates this ability to scrutinize women,” Ms. Eck said. “It makes it acceptable for someone who’s supposed to be my peer and my equal to look me up and down and comment on what I’m wearing. That doesn’t feel right.”

About a third of the state legislatures in the country had written rules for how lawmakers, staff members and visitors were supposed to dress when they were on the statehouse floor, according to a 2006 survey by the National Conference of State Legislatures, the most recent nationwide look at the issue. Others had unwritten codes for what not to wear.

Most simply called for business attire, but some were quite particular, according to the survey. New Jersey asked state senators to wear suits, not sport coats. Pennsylvania let House members take off their jackets on the floor, but they had to put them on again to speak. Women in Ohio could not wear sleeveless shirts, but short sleeves were fine. In Georgia, suit coats for men and “dignified dress” for women were expected.

Things do ease up at the week’s end. Oregon lets Senate pages wear navy polos on Fridays, and lawmakers in Hawaii are allowed to wear Hawaiian shirts on Aloha Fridays.

Montana’s one-page list of fashion guidelines (officials say they are not formal rules) were handed down Dec. 5 in what Representative Keith Regier, the House Republican majority leader, said was a response to questions from newly elected lawmakers about what to wear on the floor.