Democratic socialist U.S. Sen. Bernie Sanders and United Auto Workers President Shawn Fain have joined forces to push a “32-hour workweek with no loss in pay.”

They essentially want a four-day work week, which the UAW demanded (but didn’t get) after striking against the Big Three automakers.

Now, the senator has introduced legislation to the same effect.

Yet, neither Sanders nor his union ally understand the damage they’ll do to the workers they claim to champion — and both are being hypocritical.

The dynamic duo blame “intense opposition from corporate America” and greed for the United States not having the policy in place already.

Yet both Sanders and Fain are apparently greedy themselves, since they oversee workplaces that violate the very policy they want to mandate nationwide.

At the time of this writing, the UAW has several career opportunities available. Nearly all the full-time jobs note that they are “Monday to Friday” for an “8-hour shift.” In other words, if you want to work for the United Auto Workers, you better be ready to work five days a week for at least 40 hours.

As for Sanders, his public job applications are vague about how many actual workdays and hours he requires from his employees. But it’s notable that recent reviews from staff members frequently cite “long hours” and “long workweeks” among the cons of working for him. It’s not uncommon for Capitol Hill offices to have 40-, 50- or even 60-hour workweeks.

If Sanders and Fain believed fewer hours for the same pay makes sense, they would do it for the jobs they offer.

They want to force others to do what they refuse to do.

That’s hypocrisy.

It also shows that they don’t believe their own arguments. It seems a shorter work week only boosts productivity for other people’s jobs.

Besides their hypocrisy, Sanders and Fain have based their demands on a false reading of history. In a recent op-ed, they argued that, while productivity has risen, wages haven’t, and working hours haven’t dropped.

That’s wrong on both counts.

The typical American worker now works five fewer hours per week compared to the 1960s. And real household income is up by more than 30% in the last 40 years.

At the same time, the typical job is generally less physically taxing than it used to be.

Sanders and Fain say “nothing has changed” since the 1940s, but workers are better off in essentially every respect.

The question is why.

Americans have been working less and making more for decades, but not because of government intervention or unionization, which has plummeted. Rather, Americans are better off because of the free market.

Our free economy is continually creating better jobs, higher pay, better benefits, fewer hours, easier schedules, and so on. Businesses offer those perks because they’re competing over workers, and, as productivity rises, they’re continually able to offer more. Every worker is different, with varied interests, aptitudes, and values. They make tradeoffs with employers about what works best for them, and, over time, more workers get more of what they want.

Sanders and Fain want to pretend those tradeoffs don’t exist, as if government can give everything to everyone without any associated costs or consequences.

Yet forcing employers to let workers have fewer hours for the same pay would lead to decisions that aren’t in workers’ interests. That means job cuts, benefit reductions, small business closures, and more. Businesses don’t want to do that, yet, under the Sanders-Fain 32-hour work week, they’d have no choice.

Sanders and Fain should ask themselves how their proposal would affect their own offices. They’d have to make hard choices, depriving people of valuable career opportunities and experience while hurting their own ability to achieve their goals.

And what’s true for them is true for every workplace and worker in America.

Before a socialist senator and a struggling labor union force the economy down a dangerous road, they should blaze the trail themselves.

It won’t be long before they shift into reverse.

Jarrett Skorup is the vice president for marketing and communications at the Mackinac Center for Public Policy.