Sen. Pat Toomey owes a good part of his political longevity to his chameleonlike ability to appear to be whatever he needs to be at the moment. Look at his various hues on gun control. Toomey's co-sponsorship of a modest background-check bill hasn't dropped him from the NRA's best buddies list. The gun lobby knows it can count on him to oppose bills that would have more impact.

Toomey is similarly walking a tightrope on tariffs. The senator from a steel-producing state might be expected to support President Trump's push for tariffs on steel and aluminum imports. But the former head of the anti-tariff Club for Growth has been rather meek. "I would urge us to go very cautiously here," Toomey said of Trump's proposal.

Caution is warranted. But not when it comes to Toomey's clearly stating his position. If he thinks Trump's tariffs are a bad idea, he needs to say it louder. There is a good case against Trump's protectionist strategy. Toomey argued against tariffs many times on behalf of the Club for Growth. Has political expediency now tied his tongue?

Trump is responding to accusations by the United Steelworkers and others that Chinese steel is being dumped in the United States at low, artificially set prices. The USW says that has cost American steelworkers more than 14,000 jobs since 2015. A USW report contends China has increased its steelmaking capacity since 2000 to 1.2 billion tons annually — 10 times the U.S. capacity.

Trump's proposed dumping solution – 25 percent tariffs on imported steel and 10 percent on aluminum – will likely only make matters worse. President George H.W. Bush in 2002 imposed tariffs ranging up to 30 percent on imported steel. Bush's tariffs drove up the price of U.S. products made with steel by as much as 40 percent and led to thousands of Americans who manufactured those products losing their jobs.

Beyond that, Trump's tariffs would be a slap in the face to allies that have also accused China of dumping steel. British Prime Minister Theresa May called Trump Sunday to raise her "deep concern" and stress that "multilateral action was the only way to resolve the problem."

May's call apparently didn't move Trump, who instead pivoted to Mexico and Canada, saying those neighbors will only escape tariffs if they agree to new terms in the North American Free Trade Agreement. Trump also demanded that Mexico do more to prevent drugs from entering the United States.

Tariffs would be a particularly hard blow to Canada, which supplies 16 percent of the steel imported by this country. But Canada isn't accused of steel dumping. That culprit is China, which provides less than 2 percent of our imported steel. Trump isn't wrong to address that problem, but doing it alone and starting a trade war that will drive up prices and cost jobs in his own country isn't the right way.

Supposedly anti-tariff Republicans like Toomey seem afraid to oppose Trump, even though they are on record as taking a different point of view. Toomey may not want to anger Pennsylvania workers affected by steel dumping. But being coy about his long-held opposition to tariffs can only serve as evidence for those who accuse him of putting political interests above principles.