“You are at war when you are attacked,” Canadian Prime Minister Mark Carney said on Aug. 22, a day after trade talks with the United States collapsed on the back of new tariff demands from the White House and the US implemented 50% tariffs on selected Canadian goods.

President Donald Trump in response told Canadians to “fall in line” or face consequences "far worse" than the new existing tariffs.

It sure appears that there will be a full-on trade war between the US and Canada.

But the US political calendar may dictate terms otherwise to Trump.

For the Republican Party which Trump leads, a great deal rides on the coming US midterm elections.

The Democrats will almost surely win the House, following which investigations of the Trump administration and calls for impeachment will immediately follow.

And if the Democrats take the Senate, too, that allows further investigations as well as the ability to block new appointments.

At this stage in the political cycle, major policy decisions are subject to a political lens during the “silly season” of US elections. In this case, silly turns deadly serious to the Grand Old Party's (GOP) political chances.

President Trump certainly knows what’s at stake.

On the same day that Carney made his observations that war had been declared on Canada, Trump again said the Democrats would try to impeach him if they win the midterm elections in November and gain control of Congress.

"So you're going to lose everything. I'm going to have to go through impeachment," Trump said at a rally in South Carolina.

With all this riding on the outcome of the coming elections, many predicted that would push President Trump to find a compromise allowing him to withdraw his threat of levying 50% tariffs against key Canadian products.

With the US agricultural sector already getting punished from the impact of the US war on Iran, the prevailing wisdom foresaw an agreement with Canada to prevent tariffs which would impact that sector from going into effect.

Not so.

Some US$20 billion of Canada’s exports to its largest trading partner and longtime ally are now subject to those tariffs, which came into effect on Aug. 22 when the talks collapsed.

And, for the second time since Trump began his worldwide tariff war, Canada fought back, making it and China the only two countries in the world so far to stand up to Trump and retaliate.

“While reporting suggests Trump is concerned about Democrats controlling the House and the Senate, his actions are not making a Democratic victory less likely — if anything, he's undermining his own party's chances,” said Kyle Kondik, managing editor of the closely read non-partisan election-forecasting newsletter Sabato’s Crystal Ball at the University of Virginia Center for Politics.

Coming just as the midterms kick into gear, Canada openly retaliating against US trade policy will test if American politics and Trump’s fear of being impeached a third time will impact his final position on a tariff negotiation.

"Trump announcing 50% tariffs on the eve of voters just starting to pay attention to the midterms did not take into account political considerations,” analyzed Thurgood Marshall, Jr., who served as White House Cabinet Secretary from 1997 to 2001.

Now, businesses and consumers on both sides of the border, and Republicans running in key swing states, hope the final decision-maker keeps his eye on the electoral ball.

“Canada has its own leverage over the United States, and with its public supporting Canada standing up against the United States, it is unlikely to back down,” said Barbara Weisel, a scholar at the Asia Program of the Carnegie Endowment for International Peace who previously served as Assistant US Trade Representative for Southeast Asia and the Pacific. “The looming US midterms only reinforce that calculation.”

The Canadians know this.

Canadian Industry Minister Mélanie Joly made that clear. “We’re also targeting products that will target states in the US. And so we’re being wise and strategic to put political pressure, and that’s why we think it’s the right thing to do right now,” she told reporters.

The Republican disadvantage

Eleven of the 13 US federal elections this century resulted in the change in control of the House, Senate, or White House.

“As soon as Trump got elected, history suggested Democrats would be favored to flip the House in 2026 and, despite redistricting helping Republicans, Democrats remain favored to flip the House,” Kondik told us.

The President’s approval rating is a key indicator of the likely midterm election results for the House. A single House candidate faces tough odds to put enough distance between himself and an unpopular President from his own party, even in marginally competitive districts.

In 2018, the year of midterms in the first Trump administration, when Trump's approval rating was roughly 40%, Republicans lost 40 seats.

Now, Trump’s approval rating sinks even lower.

A Reuters/Ipsos poll concluded on Aug. 17 showed just 33% of Americans approve of his job performance.

With the President dragging them down and the Democrats needing to pick up just six seats, Republicans are nearly certain to lose their House majority.

With only one Senate seat in any given state on this year’s midterm ballot, Republican US Senators have a greater opportunity to differentiate themselves from their President.

In 2018, even with Trump at a 40% approval rating, the Republicans lost only two seats in the Senate.

If they could replicate that performance this year, they would maintain the majority. To do so, they need to convince voters that on the issue voters care about most — for many, their pocketbook — they are the better candidate.

Canada’s outsize impact

Democrats need a net gain of four seats to win the Senate.

That means that if they hold all their existing seats, and flip four, they control the upper chamber.

With a former governor the nominee with a massive polling lead in North Carolina, Democrats have a likely opening to pick up the Tar Heel State.

If they simultaneously lose Michigan, a seat they now hold which rates as a toss-up, they need to flip four others.

That means Democrats need to win four of the following: Alaska, Iowa, Maine, Ohio, and Texas.

In any other year, this would be a near-impossible political feat.

Democrats have not won a Senate race in Alaska or Iowa since 2008, or in Texas since 1988.

Current polls still rate each of these states a toss-up (RealClearPolitics as of Aug. 25):

Alaska: Pelota (D) +2.0 over Sullivan (R)
Iowa: Hinson (R) +0.7 over Turek (D)
Maine: Jackson (D) +2.3 over Collins (R)
Ohio: Brown (D) +0.6 over Husted (R)
Texas: Talarico (D) +1.2 over Paxton (R)

The Republicans have no margin for error.

Polling this far out may not prove to be dispositive, but with the direction all going one way, Democratic chances look better than anyone expected a year ago.

With four of these five states very reliant on trade with Canada, Trump’s trade war with Canada could swing the election against the GOP.

“Farmageddon” for states that trade with Canada

Foreign policy, let alone tariffs, do not typically matter much in US elections. These are not seen as a factor that visibly impact voters’ daily lives.

The economy, however, sits as the number one issue for voters this year, as so in most US elections.

An average of polls by the Cook Political Report found in July that Trump's approval rating on the economy sits at only 35% approval versus roughly 61% disapproval.

The Democrats need to show voters how tariffs fit into this pattern of the executive branch acting against their needs in the states that would be most impacted by this trade war.

Democrats are well positioned to show voters how tariffs exacerbate affordability challenges.

Canada took 30% of Iowa's total goods exports in 2025 — Iowa’s single largest foreign market.

Democratic Senate candidate Josh Turek places tariffs front and center in the campaign: "It is what I'm calling a Farmageddon. It is a second farm crisis. Because of the chaotic tariffs, we (in Iowa) now lead the nation in farm foreclosures.”

Ohio faces as much exposure — it exported US$17.5 billion in goods to Canada in 2025 – 31% of the Buckeye State's total goods exports.

Now, with 50% tariffs on Canada in force, former Democratic US Senator Sherrod Brown runs narrowly ahead to get back to the Senate after losing two years ago.

Appearing alongside Vice President JD Vance at a Cleveland-Cliffs steel plant on Aug. 21, Republican Senator Jon Husted blamed Ohio's rising electricity bills on power-plant closures under Presidents Barack Obama and Joe Biden and pointed to the plant's billion-dollar expansion as proof that Trump's manufacturing agenda works.

Husted picked the fight he thinks he can win — pinning utility costs on Democrats — rather than the one, tariffs, where the numbers contradict him.

We shall see if that strategy works.

Maine's exposure is just as direct. Sen. Susan Collins’ office puts the state's non-petroleum imports from Canada alone at roughly US$2 billion a year. In an April 2025 floor speech backing a resolution to kill Trump’s declaration of an emergency justifying tariffs, she said, “Our consumers, our manufacturers, our lobstermen, our blueberry growers, our potato farmers, will pay the price."

After negotiations collapsed last week, she warned again, "The on-again, off-again trade talks between the US and Canada lead to higher costs, risk, and uncertainty for Maine businesses."

Alaska is just as entangled with Canada as the other three. Its seafood industry relies on Canadian shipping routes, and the state's legislature in a bipartisan resolution had explicitly rejected the idea of Canada becoming the 51st state, one of Trump’s favored threats belittling Canadian independence, and opposed "restrictive trade measures."

But still, Alaska's Republicans have mostly stuck with Trump — for now.

Across all four states, tariffs are costing Republicans politically, whether they respond by criticizing the policy or avoiding its mention.

Political analysts now watch whether fear of voter backlash on Election Day will outweigh loyalty to the White House when the campaign heats up. They will watch whether Republicans turn against Trump on Canada tariffs and/or actively seek to avert conflagration on Sept. 8.

As Carney plays offense, will Trump put tariffs over party?

Carney’s move to matching Trump’s tariffs puts maximum pressure on Trump allies. And it will build.

Carney so far appears to be playing astute brinkmanship, including imposing the Canadian implementation date of Sept. 8 to give time for Trump to find a face-saving compromise.

No deal indicates Trump continues to believe his tariff policy is a winning strategy, regardless of warnings that it risks his party’s chances of keeping a Republican Senate — and opening himself to the personal risk of impeachment.

Mike McCurry, veteran of numerous presidential campaigns and White House Press Secretary under Bill Clinton, strikes a note of caution on forecasting the elections’ outcome.

“I suspect much will change in the next nine weeks, including Trump’s mercurial approach to tariffs,” he said. “We are going to shift to a ground game that will be more important than the national debate.”

Indeed, there are advantages held by Republicans going into the midterms: They have an overwhelming cash advantage. And candidates aligned with the Democratic Socialists of America running and winning in Democratic primaries could damage the Democratic Party’s brand, already unpopular in some races.

Still, Trump’s trade aggression could help make up for Democratic weaknesses.

"There is a growing realization among independent voters that the rosy economic characterizations President Trump employs fail to match reality,” Marshall said. “The rising prices resulting from these tariffs will only reinforce that realization. Even without an alternative economic plan beyond 'anything but Trump,' the political environment alone may be enough for Democrats to make significant gains."

Even those who believe Trump recognizes a “Blue Wave” election hurts him personally and politically do not expect the trade tensions between the US and Canada to be fully resolved any time before Trump leaves office.

Trade and market analysts expect this trade war to continue and potentially even escalate. Trump has the upper hand as the US market remains too critical for countries like Canada to abandon.

But politics points to a near-term truce.

Most policy bends to politics close to an election. Even the President’s love of tariffs may not run deep enough to resist it.

One thing we know: When it comes to Trump’s America First trade policy, while America’s voters may be able to check out for now, its trading partners can never leave.