Republicans in control of Congress have put up with a lot in trying to appease President Trump, the man practically none of them wanted to get the party’s nomination, but found themselves backing when he did.

They’ve sat silent when Trump refused to impose the sanctions passed overwhelmingly by Congress to punish Russia for meddling in the 2016 election and discourage it from its plans to continue to do so in the lead up to the 2018 campaign.

Republicans braved the embarrassment of our U.S. president bragging about his bigger nuclear button in trying to one-up the unhinged North Korean despot in a dangerous game of nuclear chicken.

They have watched him propose dramatic policy shifts on issues such as gun control and how to deal with U.S. residents brought here illegally as children, only to shift again and undermine legislative efforts to convert rhetoric into policy.

But because this latest Trump move — imposing 25 percent tariffs on steel and 10 percent on aluminum imports, explicitly inviting a trade war — strays so far from Republican orthodoxy and is so needless and potentially reckless, Republicans must take a stand. If they don’t draw a line here, the Republican leadership in the Senate and House can expect Trump to impose more trade restrictions when other nations, many of them our allies, inevitably respond.

If Congress does not act, Trump will get his trade war. It won’t be “good,” as the president claims. It will slow the economic expansion, unnerve the markets, destabilize alliances, and cost more American jobs than it saves. Things made of metal will cost more, adding to inflationary pressures already fueled by the big tax cuts Congress recently passed and the president signed.

The Republican leaders know this, but will they do something about it?

“There’s a high level of concern about interfering with what appears to be an economy that’s taking off in every respect,” said Republican Senate Majority Leader Mitch McConnell of Kentucky.

“We are extremely worried about the consequences of a trade war and are urging the White House to not advance this plan. The new tax reform law has boosted the economy and we certainly don’t want to jeopardize those gains,” House Speaker Paul Ryan, R-Wisconsin, said in a statement released by his office.

The U.S. Constitution is clear on who should be regulating trade, and it’s not the president.

“The Congress shall have the power to regulate Commerce with Foreign Nations,” flatly states Article I, Section 8.

But Congress, in a series of bills passed over more than a century, has surrendered its authority by giving presidents legal justifications to regulate trade without congressional action. The Trump administration contends imported metal threatens national security.

Congress can reclaim its authority by blocking Trump’s tariffs or at least targeting them toward the major offender, China, which has been dumping cheap steel into the market and transshipping — shifting metals from one ship to another — to cover its import tracks.

Right now, the tariffs target important allies and neighbors. Canada is the top steel importer at $5.1 billion last year, South Korea second at $2.8 billion, then Mexico at $2.5 billion.

Despite steel imports, the United States actually ran a $7.7 billion trade surplus with Canada in 2016, and 2017 numbers are expected to be similar when calculated. Why invite Canada to approve retaliatory tariffs and endanger that surplus?

And while it is true the latest numbers show a $63 billion trade deficit with Mexico, that is not a necessarily a bad thing. A strong and stable Mexican economy benefits the North American continent and reduces illegal emigration pressures, which should be a Trump goal.

As for South Korea, does the U.S. really want to destabilize the economy of its ally at a time when it, and the United States, is trying to deal with a nuclear saber-rattling North Korea?

Yes, Trump threatened to get tough on trade and impose tariffs when campaigning, but not many in Congress did. His tariff “solution” lacks a problem. The nation’s $566 billion trade deficit last year is not alarming in the context of the U.S. economy, which produced $19.4 trillion in economic output in 2017.

The Associated Press reports that the U.S. steel industry last year earned more than $2.8 billion, up from $714 million in 2016, according to the U.S. Commerce Department. The industry added about 8,000 jobs last year.

And according to Commerce, exports support 11.5 million jobs, 3 million of them tied to free trade agreements, jobs that could well start to decline if Congress does not push back.

The Day editorial board meets with political, business and community leaders to formulate editorial viewpoints. It is composed of President and Publisher Timothy Dwyer, Executive Editor Izaskun E. Larraneta, Owen Poole, copy editor, and Lisa McGinley, retired deputy managing editor. The board operates independently from The Day newsroom.