Three years after completing a tour of duty in Iraq, Marcus Edgerson is poor.

The 24-year-old veteran supports his wife and 4-month-old son working part-time at the Walmart in Hallandale Beach. He earns $7.70 an hour — three cents more than Florida’s minimum wage.

“I fought for my country so we could live well, but then I come home and we’re living in poverty,” he said. “I can’t take care of my family, and that’s not right.”

Edgerson joined a rally at downtown Miami’s Bayfront Park to mark the third anniversary of the last time Congress raised the federal minimum wage. About 200 people turned up for the demonstration — one of many that took place across the country Tuesday in support of proposals by Sen. Tom Harkin, D-Iowa, and Rep. George Miller, D-Calif., to increase the national minimum wage from $7.25 an hour to $9.80 by 2014. Their proposals would also index the minimum wage to inflation.

Florida’s minimum wage is higher than the national one, and is already linked to inflation. If the proposed federal increase is adopted, the national minimum wage would surpass and replace Florida’s.

Such an increase would raise the annual pay for a full-time minimum wage employee from about $15,000 to $20,000, according to the Economic Policy Institute. This would put an extra $100 a week in the pockets of the 20 million Americans who earn minimum wage.

The most common argument in support of the measure is to compensate those at the lower end of the pay scale more for their work so that they have money to spend, thus increasing demand for goods and services. The money spent on higher wages for the poor would immediately “recirculate back into our economy,” said Eric Brakken, director of 1Miami, a collection of community groups that organized the rally.

Opponents of the proposal say that increasing the minimum wage would make it harder to create jobs in an economy where unemployment is still uncomfortably high. If workers must be paid more, fewer might be hired, they say.

Brakken dismissed this argument, saying that economists should be concerned with the quality of jobs that are created, not just the number of positions. Many of the janitors and other low-wage workers at the rally on Tuesday told stories of losing their full-time jobs with benefits so that companies could take on more part-time workers who would cost employers less.

Edgerson, the veteran, said if the minimum wage were increased, it would help him buy the basics for his young family. At the top of his list is a driver’s license, which will cost him $250 since he was fined for not having the car insurance he couldn’t afford. Without a driver’s license, he has little chance of getting a better job, and he has to work for Walmart for a full year before he can be hired full time.

“It’s frustrating that I don’t get paid much for my hard work,” he said. “I like to help people, and they appreciate the customer service. But the company, they don’t appreciate the work I do for them. . . . If I were not out there, they wouldn’t make their money.”