They're pretty great--and in a lot of different ways! Harold Meyerson has an article at The American Prospect on unions and voting in 2020, based on a CAP report (linked to below) that I co-authored with Aurelia Glass and David Madland.
"A new study out today from the Center for American Progress Action Fund reveals that one of the constants of American electoral politics is still constant: Union voters still vote more Democratic than their non-union counterparts. Despite Democratic hand-wringing over the flight of working-class men to Republican ranks, an in-depth study of the 2020 presidential vote by Aurelia Glass, David Madland, and Ruy Teixeira reveals that unions were indeed an electoral bulwark against the much-feared drift toward Trump....
As Democrats ponder how to win more support among white and Hispanic working-class voters in particular, the ability of unions to produce more Democratic voters in those groups shows that the appeals of white supremacy and the war on wokeness can be countered in part by the kind of clear economic messaging that unions deliver. Plainly, Democrats themselves can’t deliver such messages as credibly as unions do. When unions speak to members through shop stewards and through friends at the worksite, the message isn’t being delivered by a Democratic establishment that some see as culturally alien and disrespectful. It’s being delivered by one’s peers.
Such messengers are needed now more than ever. The exit polls that I wrote about in the 1980s showed a substantially wider gap between working-class white union members and nonmembers than the six-point margin that divided them in 2020. That, though, was before the decades of economic stagnation and abandonment that befell this group of voters, before they fell prey to deaths of despair and right-wing media (Limbaugh, Fox, social). Democrats can’t do much about that right-wing media, but, as the Biden administration is the first since Harry Truman’s to realize, they had better do their damnedest to bolster unions any way they can."