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

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.

The 45,000 dockworkers who went on strike Tuesday for the first time in decades at 36 U.S. ports from Maine to Texas may wield the upper hand in their standoff with port operators over wages and the use of automation.