Big business is objecting to the brewing trade war.

The US Chamber of Commerce dramatically broke with President Trump on Monday with an ad campaign attacking the White House’s protective tariffs, as member companies see themselves as losers rather than winners.

The campaign, which declares “Trade works. Tariffs don’t,” is a rare break for a group that usually confines itself to nuts-and-bolts business issues. It is the largest lobbying organization in the country with more than 3 million members.

“Tariffs are beginning to take a toll on American businesses, workers, farmers and consumers as overseas markets close to American-made products and prices increase here at home,” Chief Executive Thomas J. Donohue. “Tariffs are simply taxes that raise prices for everyone.”

The campaign directs readers to a Web site, www.thewrongapproach.com, with hopes they will join the fight by e-mailing their congressional representatives.

This blast from a surprise source comes as the Trump administration is in the process of ripping up old trade agreements, including floating a bill that would end membership in the World Trade Organization.

As a result, countries around the world, including leading trading partners like China and Canada, are announcing planned retaliation for any increases in imports.

According to the Chamber, $75 billion in US goods are subject to retaliatory tariffs, which would then raise prices for American consumers.

The pointed campaign is an unusual step into the politics of trade for the group, whose support helped the White House in its successful effort last year to lower the corporate tax rate.

For example, the Web site highlights the effects of a trade war on Alabama, Michigan, Pennsylvania, South Carolina, Texas and Wisconsin — six states that produce more than $1 billion in tariff-threatened goods and are vital to a Republican presidential victory in 2020.

Some of the administration’s tariffs on foreign goods have already taken effect — and the unforeseen repercussions are raising alarms among US businesses large and small.

For example, Maine lobstermen are worried a retaliatory 25 percent tariff on American seafood by China will make their catches less competitive in the growing Asian market.

Companies like Harley Davidson, General Motors, and even Asheville, NC-based musical instrument-maker Moog have threatened to cut jobs or move operations out of the country, saying tariffs will make it too expensive to do business in the US.

Heinz Ketchup, Jack Daniels bourbon, and even Campbell’s soup are all expected to get hit by new Canadian tariffs.

The Chamber’s tariff tirade isn’t corporate America’s first revolt against the Trump administration’s business plans.

The Business Roundtable, a lobby group led by JPMorgan Chase Chief Executive Jamie Dimon, also has attacked the tit-for-tat trade policy.

“Risking a trade war with more tariffs will only invite more retaliation that will cause significant harm to the US economy,” the organization said last month.