Quoting from a lament in The Nation by Sean McElwee, Stephen Green quips the inference:

It’s nice to see the Left acknowledge, even tacitly, that they can’t win without the advantage of legalized theft against the workingman.

Here’s McElwee:

In line with previous research by Roland Zullo, who found that right-to-work and limitations on collective bargaining make it more difficult for unions to bolster turnout, this research found that right-to-work laws reduce turnout in presidential elections by 2 to 3 percent. Indeed, studying individual-level survey data, the authors found that the share of blue-collar workers reporting a get-out-the-vote contact declined by 11 percent following the passage of right-to-work laws, with no concomitant effect on white-collar workers.

The share of campaign contributions from private-sector unions also drops by 1 to 2 percent, as does fundraising by Democratic candidates in state and local races.

The effects aren’t impactful just for unions and the Democratic Party but also for the progressive movement more broadly. Working-class candidates—who past research finds are more likely to be progressive on economic issues—are less likely to win elected office after the passage of a right-to-work law. Right-to-work states have between 1 and 3 percent fewer working-class elected officials (defined as working in a non-professional, blue-collar job before running for office) in the legislature, and send fewer working-class candidates to the US House of Representatives.

So, when the large portion of the population that has been forced to join a union in order to work is given the opportunity to work without contributing to a union, money and campaign support for Democrat and far-left candidates drops.

I’ve been saying for a while, now, that employee services is really just the way in which modern labor unions (particularly those in the public sector) raise money and build leverage.  Their real mission is partisan politics and advancing a left-wing ideology. The above findings certainly don’t contradict that theory.