WASHINGTON — Some manufacturers and retailers are urging President Joe Biden to invoke a 1947 law as a way to suspend a strike by 45,000 dockworkers that has shut down 36 U.S. ports from Maine to Texas.

At issue is Section 206 of the Labor Management Relations Act of 1947, better known as the Taft-Hartley Act. The law authorizes a president to seek a court order for an 80-day cooling-off period for companies and unions to try to resolve their differences. Biden has said, though, that he won’t intervene in the strike.

Taft-Hartley was meant to curb the power of unions The law was introduced by two Republicans — Sen. Robert Taft of Ohio and Rep. Fred Hartley Jr.

of New Jersey — in the aftermath of World War II. It followed a series of strikes in 1945 and 1946 by workers who demanded better pay and working conditions after the privations of wartime. President Harry Truman opposed Taft-Hartley, but his veto was overridden by Congress.

In addition to authorizing a president to intervene in strikes, the law banned “closed shops,” which require employers to hire only union workers. The ban allowed workers to refuse to join a union. Taft-Hartley also barred “secondary boycotts,’’ thereby making it illegal for unions to pressure neutral companies to stop doing business with an employer that was targeted in a strike.

It also required union leaders to sign affidavits declaring that they did not support the Communist Party. Presidents can target a strike that may “imp.