Joe Biden

The vice president donned a black-and-gold United Steelworkers union hat and told hundreds of union members that the gap between the wealthy and poor was hurting the nation.

"The tax code's not fair. It's simply not fair," Biden said in a city long associated with organized labor. "The wealthy aren't paying their fair share. There used to be one America."

Biden later marched throughout the city's downtown, hearing encouraging words along the parade route.

Biden's comments came at a memorial to the five servicemen killed in a shooting rampage by Kuwait-born Muhammad Youssef Abdulazeez.

"These perverse ideologues, warped theocrats, they may be able to inspire a single lone wolf to commit a savage act, but they can never, never threaten who we are," Biden said. "When this perverted jihadist struck, everyone responded."

 But Biden has yet to tell his staff whether he will run or personally ask them to do any planning for a potential campaign, according to several people close to the vice president.