NEW YORK CITY is one of the world’s great centers of fashion. So it’s not surprising that New York’s senior senator, Charles E. Schumer, would take an interest in fashion designers. Last week he introduced legislation that would rewrite copyright law to cover their designs. But his bill could hurt the fashion industry more than it would help, and raise consumer prices along the way.

It strikes many people as strange that fashion designs are not already protected against copying. Creative artists like musicians and filmmakers argue, quite persuasively, that their success requires copyright protection for their work. If others could steal it, they say, innovation would grind to a halt.

But there is a good reason that fashion designs have never been protected by copyright. Some designers have lost sales to knockoffs, but the copying of designs has not been a serious threat to the survival of the industry. To the contrary, much of the growth and creativity in the industry depends on imitation.

Why is that? Because of something we all know instinctively about fashion. As Shakespeare put it, “The fashion wears out more apparel than the man.” That is, many people buy new clothes not because they need them, but only to keep up with the latest style.