After months of fruitless efforts with the Trump White House, Prime Minister Justin Trudeau appears ready to make Canada's case for the lifting of steel and aluminum tariffs directly to allies in Congress and across the U.S., as U.S. workers and businesses also feel the sting of the border taxes.

In a wide-ranging interview with The National's Rosemary Barton that airs Sunday, Trudeau talked about the duties that were slapped on Canada, supposedly because steel and aluminum posed a risk to U.S. national security — and his game plan to have them removed.

"I mean we, obviously, want to get rid of those steel and aluminum tariffs," he said. "But we also see the path toward ratification as a place where there are continued conversations from members of Congress, from business or associations in the U.S., from governors who also want to see these tariffs gone, and we're going to keep working on that."

"Every step of the way there continue to be levers to pull on and we're going to continue to do what Canadians expect us to do, which is look at every opportunity to stand up for our interests."

Tariffs of 25 per cent on steel and 10 per cent on aluminum imports from Canada were put in place on May 31, taking effect the next day.

Every step of the way there continue to be levers to pull on. - Prime Minister Justin Trudeau

That same night, Canada announced its retaliation: On July 1, dollar-for-dollar countermeasures would be imposed on up to $16.6 billion in U.S. goods, including steel, aluminum and other products like whisky, chocolate, and orange juice.

It was a calculated retaliation, aimed at key Republican districts — like in Kentucky and Wisconsin — and other swing states like Florida.

Trade and tariffs

Last year, the Canadian steel industry employed more than 23,000 workers and contributed over $4 billion to the country's GDP. Canada also buys more U.S. steel than any other country in the world.

To try to soften the blow, the federal government announced a compensation package for Canada's steel and aluminum industries in June.

Trudeau government officials made it clear from the start, if the U.S. lifted their "unjust and illegal" tariffs, the Canadian ones would disappear as well.

The National's Rosemary Barton interviews the prime minister, including asking about the U.S. tariffs on Canadian steel and aluminum. (Evan Mitsui/CBC)

But as the weeks and months passed, it became clear Donald Trump was ready to pour more gas on the fire.

"I don't want to do anything bad to Canada. I can — all I have to do is tax cars — it would be devastating," he said in September.

The president threatened a 25 per cent duty on autos, which experts said would cripple the Canadian industry.

All the tariffs were introduced under the guise of a little-used section 232 of the 1962 Trade Expansion Act. The clause gives the president power to impose duties on foreign products if the White House deems they would "threaten to impair the national security."

Those car tariffs never materialized, and at the end of NAFTA re-negotiations, Canada was able to secure an exemption for a certain number of auto parts from possible future auto tariffs.

Prodding Trump on tariffs

Foreign Affairs Minister Chrystia Freeland long maintained the tariff discussions were separate from the trade deal negotiations, but in the final days before the new CUSMA pact was reached, Canada sought a tariff shield from the U.S. during trade meetings in Washington.

Trudeau has also spoken directly with Trump about the tariffs on several occasions.

There were reports from Mexico that the tariffs might be lifted once the CUSMA was signed, but as the three North American leaders put pens (or Sharpies, in the case of Trump) to paper at the G20 summit at the end of November the tariffs remained.

This summer the U.S. filed complaints at the World Trade Organization against Canada, China, the European Union, Mexico and Turkey in response to retaliatory tariffs launched against the United States.

The prime minister is unfazed.

"We will not rest while those barriers remain," Trudeau said at the G20.

And as General Motors plants across the continent, including one in Oshawa, Ont., prepare to close, Trudeau used that issue to prod Trump once more on the tariffs.

"Donald, it's all the more reason why we need to keep working to remove the tariffs on steel and aluminum between our countries."

Watch The National's full interview with Prime Minister Justin Trudeau at 9 p.m. ET on CBC News Network, or on CBC's YouTube, Facebook and Twitter.