Open this photo in gallery:

Michigan Democratic Senate candidate Abdul El-Sayed speaks at a campaign rally at the Majestic Theatre in Detroit on Monday.Julia Demaree Nikhinson/The Associated Press

The Ham Sandwich of Truth is a test from the sport of rowing. It can be used to decide whether a member of the crew is pulling their weight, or is dead weight.

To perform the experiment, remove one athlete from the boat. On their empty seat, place two slices of bread filled with processed luncheon meat (mustard optional). Does an eight-person shell become faster with seven rowers? Then the missing body wasn’t an engine powering the vessel forward – they were ballast, holding it back.

They were literally slower than a ham sandwich.

Analysis: Billionaire donors have changed the game in these U.S. midterms

The U.S. midterms are Tuesday, and the result should be the Democratic Party taking comfortable control of both houses of Congress. Midterm elections tend to feature swings against an incumbent president, and this year Americans are particularly unhappy with the incumbent.

President Donald Trump’s approval rating is far underwater. High gas and diesel prices are a particular sore point, since these are entirely a result of Mr. Trump’s decision to go to war against Iran. His trade war against Canada has been so poorly received that some GOP candidates have aired ads trying to disassociate themselves from Dear Leader’s policy.

Democrats should be cruising to victory on Tuesday, but they’ve got problems of their own. According to poll aggregations from Real Clear Politics, the Republican Party’s net favourability among voters is minus 19 per cent. Democratic Party favourability? Minus 15.6 per cent.

There are a lot of former Trump voters who regret the choice they made in 2024. To win, Democrats have to get enough of them comfortable with switching their vote.

The best election result for Canadians would be a massive Democratic victory. That would also be the best result for Americans. Mr. Trump has broken all legal and democratic norms at home, while overseas he’s been trying to trigger superpower suicide. A rubber-stamp Republican Congress has enabled a corrupt, unstable and delusional man to operate without checks or balances.

The stronger the counterweight of Congress against this White House, the better for America and the world.

Polls show Democrats on track to take control of the House, but Senate is less predictable

But the Democratic Party hasn’t made it easy for itself, or for voters inclined to consider rejecting Mr. Trump.

Democrats have been locked in an ideological civil war for the past decade. If they underperform on Tuesday – that would mean claiming only the slimmest of majorities in the House of Representatives and the Senate, or even failing to take control of the latter body – the infighting and recriminations will reach new heights.

Are the party’s most progressive and woke candidates the ham sandwich? They get outsized media attention, but are they a drag on the boat? Does the electoral power come from the Democratic Party’s moderate, centrist wing?

Or are the Democratic Socialists of America and others on the left doing a disproportionate share of the rowing? Are centrist Democrats the ham sandwich?

Even if Democrats win big, arguments will erupt over who was responsible for victory, and who victory was secured in spite of.

The Senate race where the Democratic civil war is most visible is Michigan. It’s a competitive swing state that helped put Mr. Trump in the White House in 2016 and 2024, but the last time it elected a Republican to the Senate was more than three decades ago. Given the other factors at play – the midterm tilt against incumbents, the President’s unpopularity, economic frustrations – any Democrat would have been the prohibitive favourite.

If they’d nominated a bland nobody, Senator Whozdat would be heading to Washington.

Instead, the narrow winner of the Democratic primary was Abdul El-Sayed. His economic populism is largely shared by voters and the Democratic establishment: Most Michiganders want better health care and lower prices.

But he’s also thumbed his nose at the mainstream of the party by consorting with loony-left podcasters such as Hasan Piker, and by maintaining an obsessive and at times conspiratorial focus on Israel as a source of America’s problems.

On the weekend, Democratic Congresswoman Haley Stevens, who narrowly lost to Mr. El-Sayed in the Senate primary, announced that she would be taking the unprecedented step of voting Republican in the Senate election.

A Michigan Senate seat that has been reliably Democratic for a generation would normally not have earned so much media attention, particularly in a year where the story is that Democrats need to flip at least four Republican seats in order to take control of the Senate.

Winning a seat in Michigan that they already own gains Democrats nothing. And given the built-in Democratic advantages in Michigan, Mr. El-Sayed is almost certainly going to win.

But the attention he’s received has cast shade on centrist candidates who have the far more difficult task of winning over voters in Republican-leaning states such as Texas and Iowa.

As I said, the best outcome on Tuesday night would be the biggest possible Democratic majority in both houses of Congress. The wider the majority, the better the opportunity to use the legislative process to put some brakes on Mr. Trump.

It would also ensure that, as the fight for the soul of the Democratic Party continues, the small number of far-left members are not empowered as swing votes that, to maintain a voting majority, their fellow Democrats must constantly appease.