Many lawmakers experience a moment when enough becomes enough, when the common good can no longer tolerate a wrong.

For state Representative Elizabeth A. Poirier, that moment came on the House floor, during an informal session some time ago, when a colleague, whom she declines to name, sullied the dignity of the august body with the taint of denim.

“It was,’’ she said, recalling the offending pair of blue jeans on a House member, “entirely inappropriate.’’

And so Poirier, a North Attleborough Republican, sponsored an amendment to the House rules yesterday requiring “proper’’ attire for all members whenever they are in the chamber. After her brief but passionate speech, Poirier’s colleagues approved the fashion fiat by voice vote, with no dissension.

The approval extends a sartorial mandate that had previously been in place only for formal legislative sessions, when the most substantive issues are debated.

That means no more track suits. No Bruins jerseys. No spaghetti straps.

“Different people came up to me and said, ‘Was it me you were talking about?’ — so there’s a little guilt going on here,’’ said Poirier, who often honors the chamber with bold yet tasteful ensembles accented by pearls.

Poirier said closing the chamber’s fashion loophole by specifying that “members and staff shall be required to dress in proper and appropriate attire’’ has nothing to do with money or couture, but rather “the dignity of, the whole aura of, the State House and the history of all that it means.’’

Hygiene, grooming, and “attention to detail’’ are all that she asks, “to set the bar a little higher for everyone else.’’

House Democrats, taking no issue for granted, debated the rule during a closed-door caucus before agreeing, with the blessing of Speaker Robert A. DeLeo, to embrace it on the House floor. Then they patted themselves on the back for a rare show of bipartisanship.

“In the informal sessions, in the past, there has been a little bit of lack of effort, shall we say,’’ said state Representative Garrett J. Bradley, a Hingham Democrat, who, in an orange tie and a white pocket square, served as his party’s designated point person in the debate. “I think that will be cleared up by this rule.’’

Good government, perhaps.

But some other measures debated during a daylong session yesterday on House rules did not fare so well.

Soundly defeated were proposals to require roll-call votes on tax increases; to post results of committee votes online; and to eliminate the position of speaker pro tempore, a job most recently held by a member now linked to the patronage scandal in the state Probation Department.

Michael Levenson of the Globe staff contributed to this report. Noah Bierman can be reached at nbierman@globe.com.

© Copyright 2011 Globe Newspaper Company.