Over the weekend, an inexplicably jubilant President Donald Trump declared, “A lot of steel mills are now opening up because of what I did. Steel is back, and aluminum is back.”

Wow – so fast?

The president uttered these words just days after announcing tariffs on imported steel and aluminum. This, despite the cries of outrage from such leaders in his own party as House Speaker Paul Ryan and Gary Cohn, who seized the moment by resigning from his position as Trump’s chief economic advisor.

And yet, just like that, Trump was now telling us, the steel and aluminum industries were thriving again.

We will add this to the other great lie told over the weekend by this president when he declared that 52 percent of women voted for him in 2016. The actual figure was 41 percent. The 52 percent was the number of white women.

But the lie about steel’s instant recovery is more troubling because it implies huge numbers of jobs are coming back, and chances are they are not.

As Dana Milbank wrote last week in the Washington Post, “The industry’s fortunes have waxed and waned [over the years] with the economy and the price of steel. Trade protections came and went. But steel jobs continue to vanish. That’s because the job loss has almost nothing to do with imports.”

We know about such things around here because so much of Baltimore’s economy was based on manufacturing steel, and so little remains of it.

Remember? Once upon a time, we had 30,000 people here working for Bethlehem Steel. In his book “Making Steel: Sparrows Point and the Rise and Ruin of American Industrial Might,” Mark Reutter wrote, “Out of its furnace fires came the steel for the tail fins for Chevy Bel Airs and Thunderbird convertibles, the tin plate for Campbell soup cans, the hulls of ocean tankers and Navy destroyers, the wire and girder plate of suspension bridges, and a thousand and one other products.”

But those jobs went away, didn’t they? The post-war Baltimore that once had 1,600 manufacturing establishments for working-class people has become a service economy, and jobs once handed down through the generations like family heirlooms have disappeared.

As Milbank wrote last week, “What has changed is that Americans consume far less steel – little more than half as much per capita compared with the 1970s – as improved technology means automobiles and other applications require less of it. At the same time, improved steelmaking productivity means the industry requires dramatically less labor.”

Steel production has dropped by a third over the last 40 years, but steel industry employment is down by three-quarters.

Years ago, Sparrows Point’s blast furnaces sent smoke and soot into the air around the clock. They didn’t call it pollution back then, they called it “gold dust.” It meant people were working.

But they stopped working years and years ago, and this president can claim all he wants that “steel is back” just days after he launched his tariff plan.

But saying it doesn’t mean it’s true.

A former Baltimore Sun columnist and WJZ-TV commentator, Michael Olesker is the author of six books. His most recent, “Front Stoops in the Fifties: Baltimore Legends Come of Age,” has just been re-issued in paperback by the Johns Hopkins University Press.