The U.S. Copyright Office criticized a Democratic plan to open up the market for cable boxes to third-party content providers such as Google and Amazon, saying the plan “could interfere with copyright owners’ rights to license their works.”

The office noted that the owners of video content currently have the ability to work out contractual arrangements with cable providers. But it said the rule proposed by Democrats on the Federal Communications Commission could weaken those rights and potentially make those owners vulnerable to “forms of exploitation” that could include piracy.