The Trump administration said on Wednesday that it would move forward with plans to allow states to safely import prescription drugs from Canada, for the first time.

The decision is an unusual one for a Republican administration. Progressives have long supported such a policy, but the pharmaceutical industry vehemently opposed drug imports by claiming they were unsafe. Food and Drug Administration commissioners had also opposed importing drugs intended for overseas use, citing safety issues.

In a telephone call with reporters Tuesday, Alex M. Azar II, the secretary of health and human services, described the announcement as momentous. “For the first time in history, H.H.S. and the F.D.A. are open to importation as a means to lower drug prices,” he said.

He also said, “We will not take steps that would put patients or our drug supply at risk.”

First announced in July, the proposal is still a long way from affecting consumers’ wallets. States will have to submit their own plans to the federal government for approval, to see if they are both safe and would significantly reduce costs.