NEW YORK – In just a few days, a walkout by thousands of dock workers could bring commerce to a near standstill at every major port from Boston to Houston, potentially delivering a big blow to retailers and manufacturers still struggling to find their footing in a weak economy.

More than 14,000 longshoremen are threatening to go on strike Sunday – a wide-ranging work stoppage that would immediately close cargo ports on the East Coast and the Gulf of Mexico to container ships.

The 15 ports involved in the labor dispute move more than 100 million tons of goods each year, or about 40 percent of the nation's containerized cargo traffic. Losing them to a shutdown, even for a few days, could cost the economy billions of dollars.