American flags purchased by the U.S. military must be completely made in America. As of Friday.

It’s the sort of thing that seems like it would have been formalized already. There’s a rule that governs what the Pentagon can purchase and where these things must originate, a rule that didn’t use to cover American flags.

The new policy says that American flags, “including the materials and components thereof,” have to be made in the United States.

Rep. Mike Thompson (D-Calif.), who is running for a ninth term in Congress, said on Friday that he pushed for the change because he thought it was just common sense that American flags be made in the United States.

“American flags are something we can all agree on should be made in America,” he said. “I don’t think it’s right that our military service men and women should be fighting under flags made in foreign countries.”

So he wrote a provision that puts the American flag under the aegis of the the Berry Amendment. That amendment, passed in 1941, restricts the Defense Department from buying food, clothing, fabrics, textiles or tools that aren’t grown or produced in the United States. American flags had previously not been included among that list.

This change went through as part of the $1.1 trillion omnibus appropriations bill passed by Congress and signed into law by President Obama last month. And the new policy for flags went into effect on Friday, said Mark Wright, a Pentagon spokesman.