Donald Trump campaigned hard on a promise to mount a trillion dollar project to repair/rebuild our nation’s infrastructure — roads, bridges, airports and so on. On that point there is bipartisan support, and we should all support this important proposal.

But, all these federal projects will be covered by the Davis-Bacon Act of 1931 (“D-B”), an outdated, anachronistic federal statute that mandates the payment of “prevailing wages” (read inflated “union scale”) for all workers.

This 86-year-old statute has outlived its usefulness. It unnecessarily inflates construction costs, imposes wasteful bureaucratic paperwork requirements on contractors, and allocates employment opportunities unfairly.

Suspension of Davis-Bacon for the duration of Trump’s planned public works cornucopia would save taxpayers untold billions and ensure true equal opportunity for the tens of thousands of new jobs that will be created.

The origins of D-B are a distasteful and embarrassing episode of American labor history. The bill was introduced after African-American workers from Alabama were hired by a contractor to help build a VA hospital in Representative Bacon’s New York district (he was co-sponsor of the bill and its namesake). The law was passed by Congress and ironically signed into law by President Hoover to “preserve jobs for local workers” (no matter what the additional cost to taxpayers).

There are myriad reasons why D-B should be suspended for the duration of President Trump’s proposed public works project. First, the law is outmoded. It was enacted out of fear and racism, and continues to discriminate against minorities and others who should be job eligible. For example, just one year after its passage, only 30 out of 4,100 workers on the federally funded Boulder Dam built in 1932 were African-American.

Second, D-B has cost American taxpayers at least an estimated $1.5 billion per year in inflated construction costs. Those additional costs are a mere fraction of the excess costs that lie ahead under the huge expansion of federal construction projects proposed by the Trump administration. Suspension of D-B would save tens, even hundreds of billions of dollars, depending on the ultimate scope of the program.

Third, D-B imposes unnecessary and expensive regulatory burdens on contractors. D-B requires the strict assignment of workers and payrolls on a craft-by-craft basis, thus undercutting the types of human resource flexibility that yield enhanced productivity, efficiency, and cost savings common in today’s workplace.

Finally, D-B is a dinosaur labor law that needlessly and unfairly favors unions and union workers to the disadvantage of all others. The “prevailing wage” language of the statute might as well read “UNION SCALE”.

Application of the statute to federal construction projects gives union workers an unjustifiable preference and discriminates against other capable workers. The statute allows unions unfairly to monopolize public works projects and grossly escalates the cost to taxpayers.

In short, the D-B law should be suspended for the duration of Trump’s infrastructure program, or better yet, repealed in its entirety.

(Mr. Skoning is a Chicago labor and employment lawyer.)