The strangest flirtation in Washington is the ongoing courtship between a subset of Republicans and the Teamsters union.

It could also be among the most economically destructive.

This May Day-November relationship is built around mutual neediness: Union membership is trending down.

Only 6% of today’s private-sector workers belong to a labor union, down from 10% in the mid-1990s.

Some DC Republicans, most notably Missouri Sen. Josh Hawley, reckon that if they tilt federal labor rules even further in the Teamsters’ and other unions’ favor to help them make up those losses, the unions will be moved beyond words and help the party win more elections.

Hawley in particular sees overlap in the Teamsters’ interests — particularly their ongoing crusade against self-driving cars — and his personal brew of grievance-tinged nationalism that broadly treats automation as a threat against the American worker.

The two sides consummated the romance in 2024, when Teamsters head Sean O’Brien spoke at the GOP’s national convention and the union steered a nominal amount of campaign cash to a couple dozen Republican candidates.

But are they in it for the long haul?

Labor unions including the Teamsters in 2019 compiled their political wishlist into the Protecting the Right to Organize Act, or PRO Act.

That sweeping legislation would have made it more difficult for people to work as independent contractors (and easier to unionize them instead), and would have voided state right-to-work laws, allowing unions in Texas, Florida and elsewhere to start forcing workers to pay them or lose their jobs.

The PRO Act was so radical that it never became law, even when labor-friendly Democrats controlled Congress.

Enter these Republicans.

Instead of offering flowers and chocolates, they aim to impress labor by slicing up the PRO Act and feeding it piecemeal to the rest of the GOP.

The Faster Labor Contracts Act, sponsored by Hawley and Rep. Donald Norcross (D-NJ), is the first portion.

It would allow federal mediators to essentially write union contracts for newly organized workplaces, if businesses and unions can’t agree on terms within four months of a union’s workplace-election win.

First-contract talks at businesses like Starbucks and Amazon, and even at nonprofits like New York’s Albany Medical Center, can sometimes drag out for years.

Putting a time limit on that process sounds innocuous, but it benefits union brass — and harms workers — in two key ways.

Once an employer agrees to a union contract, federal rules prevent their employees from holding another union election for almost three years, and makes it difficult if not impossible to kick the union out even after that.

Unions regularly “win” elections in American workplaces without majority support from the people they ostensibly want to represent.

After that contract has been signed, it doesn’t matter how satisfied workers are with the quality of that representation — they’re stuck.

The second issue is more sinister.

Union contracts cover a wide range of topics, including pay, benefits and work rules.

Negotiating a new agreement means sacrificing flexibility, both for employers and employees.

It’s a process that takes time.

A hard deadline gives the union extra leverage to win one of its most coveted provisions: “agency shop,” a rule (permitted in about half of states) requiring every employee to either pay the union or get fired.

That’s a financial bonanza for a union, which now often must wait for workers to approve subsequent contracts before trying to sneak agency-shop into the next deal.

And nothing would require the resulting windfall to benefit the Republicans who helped make it possible.

The New York Republicans siding with the Teamsters — Andrew Garbarino, Nick LaLota, Nick Langworthy, Mike Lawler and Nicole Malliotakis — have apparently calculated that potentially subjecting local employers to labor arm-twisting is a good bet in a tough midterm year.

The Teamsters’ political arm donated to four of the five of them last year, Politico reported.

Zooming out, promoting unionization for unionization’s sake would push private-sector businesses toward problems long associated with the public sector: rigid labor rules that make it tougher to adapt or modernize.

The likely result will be a broader drag on economic growth, with higher prices for consumers, slower innovation and weaker competitiveness for American firms internationally.

In an economy that needs flexibility to make the fullest use of technologies like AI, the last thing Washington should do is make it harder for businesses to adjust and compete with Chinese and other rivals by literally threatening to write the union contracts for them.

Americans risk mistaking the Republican-Teamsters alliance for a post-partisan project that serves the public interest.

It could soon prove that it doesn’t even serve the GOP’s.

Ken Girardin is a fellow at the Manhattan Institute.