While Clinton holds a commanding lead, there are sharp disagreements over what strategy will produce the most pro-labor president. Endorse Clinton early to get to work battling the GOP? Hold off to extract more concrete commitments? Take a chance on Sanders as a vehicle to build a mass movement? Gregory Junemann, president of the International Federation of Professional & Technical Engineers, warns against a premature endorsement. “It’s like tipping the cab driver before you get in the car—the person then has your commitment without making any promises themselves,” he says. In contrast, IAM head Buffenbarger says there’s little advantage in holding out for election season promises, because candidates don’t stick to them anyway. “When they find their way to the front door of the White House, they seem to forget about it as soon as they cross the threshold,” he says. [...]

Sanders received 65 percent support in a poll of delegates at the Utility Workers Union of America’s July convention. At IFPTE’s conference last week, says President Junemann, delegates delivered effusive speeches in favor of endorsing Sanders; the proposal was deferred to the union’s executive council, in part because some members are still holding out hope for Joe Biden. Clinton backers note she’s got grassroots support too: Weingarten cites over 3-to-1 support she received in a poll of AFT members who vote Democratic and wanted to endorse someone, and a rapturous reception at the AFT conference when the endorsement was announced.