Dockworkers began picketing at the Port of Philadelphia early Tuesday after the International Longshoremen's Association announced the union would go on strike​.

Docks in Philadelphia and all along the East Coast and Gulf Coast have ground to a halt as dockworkers strike for the first time in nearly 50 years. About 45,000 members of the International Longshoremen’s Association hit the picket line around midnight when their contacts with the owners of 36 ports expired.

Unionized dock workers in Philadelphia and other major East Coast ports are striking for the first time in nearly half a century. Why it matters: A prolonged strike could snarl supply chains and raise prices on everything from bananas to auto parts as the presidential election and holidays near.