Time is running out. Here’s how the climate movement can level up.

On an unusually warm, clear day in late September, a dozen progressive activists paddled their kayaks and boats up to to a houseboat Sen. Joe Manchin (D-WV) keeps parked on the Potomac in Washington, DC. For four days, they had been floating around the West Virginia-themed boat named “Almost Heaven” with colorful signs, calling on him to support Build Back Better, the most critical piece of climate legislation considered by Congress in over a decade. Apparently unmoved by their “We want to live” chant, Manchin finally leaned over the railing...