Teamsters Boss Has Tough Words for UPS and Sets Sights on Amazon

There is nothing subtle about Sean O’Brien’s negotiating style.

O’Brien, the incoming leader of the International Brotherhood of Teamsters, peppers his speech with words like “leverage” and “pressure” and “fight” and wants the executives over at the United Parcel Service Inc. to understand he’s not going to play as nicely as his predecessor, James P. Hoffa. There are 16 months before the Teamsters’ collective contract is set to expire with UPS, and O’Brien is already talking general strike if his demands aren’t met.

“We’ll put them on the street,” O’Brien, 49 and a fourth-generation Teamster, said in an ...