A massive crowd gathered at City Hall in Philadelphia Thursday for a May Day rally and to see Vermont Sen. Bernie Sanders speak. The "For Workers, Not Billionaires" rally on the north side of City Hall drew a large crowd and shut down streets in the area.

I’m here in Pennsylvania to tell any member of the Pennsylvania delegation that if they vote for tax breaks for billionaires and cut Medicaid ... we are going to throw them out," Sanders said.

Thursday’s rally and march comes amid economic uncertainty created by Trump’s on-again, off-again approach to tariffs — taxes on imported goods — which