Any American flag purchased by the US Defense Department from now on will be legally required to have been made in the United States.

The new law, which goes into effect on Friday, is an apparent attempt to curtail flag purchases from China, which spiked following the demand generated by the September 11, 2001 terrorist attacks in New York.

The new policy first passed last month as part of the $1.1 trillion omnibus appropriations bill, which funded the government through September 30, but the flag stipulation officially became law on Friday.

American flags have always been produced inside the US, but businesses have saved significant amounts of money by ordering them from China – a trend that became especially popular when the demand for flags increased after the 9/11 terrorist attacks.

Representative Mike Thompson (D-Calif.), who is running for a ninth term in Congress, said Friday that he was surprised the policy was not already a law.

“I thought it was appalling our Department of Defense would have flags made in other countries,” he said. “But it’s also important because we need to be making more in America.”

The new law is an update to the Berry Amendment of 1941. That amendment forbids the Defense Department from purchasing food, clothing, military uniforms, fabric, stainless steel, and hand or measuring tools produced outside the US other than in extraordinary conditions.

“American flags are something we all can agree should be made in America,” Thompson said. “I am proud to have worked to pass this law so that our men and women in uniform never have to fight under a US flag made overseas, and so that our Defense Department never again spends American tax dollars on a US flag made overseas.”

US manufacturers simply could not keep up with the amount of flags that needed to be produced during the surge of patriotism following the 2001 attacks. The market for foreign-made flags was valued at approximately $1 million per year before the World Trade Center fell, but that figure jumped to a shocking $52 million as millions of people placed new flags on their vehicles and outside their homes after 9/11.