As if raising and waving millions of Stars and Stripes was not patriotic enough at Independence Day celebrations yesterday, the flags now have to be made in the US.

The state of Minnesota has taken the most draconian action, requiring all US flags sold in the state to be of American manufacture. Violations of the law, which comes into force at the end of the year, will be punished by a $1,000 (£495) fine or 90 days in jail.

From this month, schools and colleges in Arizona are being forced to equip every classroom with a US-made Stars and Stripes - sometimes known as "Old Glory".

Tennessee state law already stipulates that any US flag bought with public money cannot be imported from another country, while similar Bills are being considered by legislators in New Jersey and Pennsylvania.

Such measures chime with the protectionist mood sweeping America. The Democrats, in particular, have become increasingly concerned about preserving manufacturing jobs that they believe are being destroyed by free trade and cheap foreign imports.

In this cause Old Glory has, as ever, emerged as a potent symbol. Last year Republicans failed by a single vote to get the two-thirds majority they needed in the US Senate for a constitutional amendment banning the burning of the flag.

The sponsor of the Minnesota legislation, the Democratic state congressman Tom Rukavina, said that his Bill was inspired by seeing flags made overseas during a memorial service for the victims of September 11, 2001.

Yesterday he was handing out 1,000 miniature flags - presumably US-made - at Independence Day parades in his district. "The biggest honour that you can give the flag is that it be made by American workers in the United States of America," he said.

"Nothing is more embarrassing to me than a plastic flag made in China. This replica of freedom we so respect should be made in this country . . . I think this Bill is about jobs, jobs for Americans."

His proposal was backed by fellow congressman Larry Howes, a descendant of Betsy Ross, the Revolutionary War seamstress who, according to American mythology, was instructed by George Washington to sew the first Stars and Stripes on to a piece of cloth. "It's time to bring the flag home," Mr Howes said.

Not surprisingly, the series of new laws is supported by the Flag Manufacturers' Association of America. It has complained about a flood of US flags, valued at $5.3 million, imported mostly from China last year.

The Chinese, whose high-speed response to market demands has made US industry look leaden-footed in recent years, appear to have spotted a gap in the market after the 9/11 attacks. In 2000 America imported $748,000 of US flags, mostly from Taiwan. In 2001, however, that figure rose to $51.7 million - mostly from China.