When the United States International Trade Commission decided on Wednesday to uphold tariffs of about 24 to 36 percent on most solar panels imported from China, the case’s proponents claimed a major victory. Domestic solar manufacturers said the duties, to be in place for five years, would make up for unfair business practices by Chinese companies that had harmed the domestic market and allow homegrown companies to hire more workers and thrive.

“This basically takes it from being just allegations of illegal activities in this industry to confirmation,” said Gordon Brinser, the chief executive of SolarWorld Industries America, the lead company that brought the case. “This was a growing industry just a couple years ago that has been basically decimated by the Chinese manufacturers.”

The Commerce Department had imposed the tariffs earlier this year after finding that Chinese solar companies had received unfair subsidies from their government and dumped solar cells below costs.

But whether the duties can help save the American solar industry is a matter of some dispute. Because they apply to panels made of Chinese-produced solar cells, Chinese companies are already avoiding the duties by assembling their panels from cells produced elsewhere, like Taiwan, even if the cell components come from China.