JERUSALEM — How short is a short skirt and who gets to decide?

These were the questions vexing members of the Israeli Knesset, or Parliament, on Wednesday as dozens of female employees arrived in above-the-knee attire to protest what they said was the Knesset guards’ sudden eagerness to enforce a longstanding dress code.

Many aides also wore thick tights or black leggings, though it was unclear if that was a nod to modesty or the bad weather.

The years-old code, which a Knesset spokesman said was recently “refreshed,” calls for dignified dress that becomes the place and bans items like shorts, ripped trousers, skimpy tops, T-shirts with political slogans, short skirts and dresses, and flip-flops.

While many Knesset members and their aides said they supported the need for a dress code, they questioned the guards’ role as the arbiters of appropriate skirt length, comparing them to the modesty police in conservative religious societies. One employee cheekily said in a radio interview that she was considering looking into jobs in Iran’s Parliament.