Donald Trump says he won't sign a deal on NAFTA until after the US mid-term elections in November. I guess the optics are better if he's fighting with Canada than waiving an agreement with us. And that, I fear, means he's getting ready to slap tariffs on our auto sector.A 20 per cent tariff would be disastrous, especially for southern Ontario. Car prices would spike, and tens of thousands of jobs would vanish. Having already been hit with steel and aluminum tariffs, Canadians are worried, but lots of serious people still think Trump is bluffing on autos.I disagree, and here's why.The European Union has a US trade surplus in autos of €35.9 billion. Mexico has an overall trade surplus of $71 billion, mostly from cars, trucks, and auto parts. And in Canada, about 1.9 million of the 2.2 million vehicles we produced last year were sold in the US.Trump claims that numbers like these show just how bad trade agreements have been for the US. America once owned the auto industry and now it foots the bill for everyone else's success.The EU, Mexico, and Canada dispute this. Trade relationships, they reply, are highly complex so that pointing to a few big numbers can be very misleading. For example, Canada may run a trade surplus in assembled vehicles, but this is offset by a deficit in the auto parts it imports from the US to build the cars.It's a fair point but, in fact, things are even more complicated than this. For instance, the same car parts can move back and forth across the border several times as pieces get added. Keeping track of the value added is so complicated that often even the experts disagree on who gets what benefits. (The same situation arises with debates over Supply Management.)As for the public, they have no idea what to believe. And this works well for Trump, who is not interested in the truth. His views on the issue were decided long ago. What he wants from Americans is support for his trade agenda and he will happily cherry pick his facts to get it. But that doesn't mean his approach to trade is just whimsical. It is not.Trump knows that modern trade relationships are complex and dynamic. Indeed, he believes that to get the most out of them, the US must be free to adjust and change along with circumstances. He is therefore opposed in principle to commitments he thinks will compromise this flexibility. The NAFTA negotiations are a case in point.A key US demand is that cars built in Canada and sold in the US have at least 50 per cent American content. Last week, the Globe and Mail reported that Canada offered to meet this demand two months ago (along with concessions on Supply Management – another sore spot for Trump).In return, Canada asked the US to withdraw a second set of demands: gutting NAFTA's dispute resolution, imposing Buy American procurement rules, and inserting a sunset clause. While Trump's economic adviser, Larry Kudlow, and Treasury Secretary Steve Mnuchin wanted to take the deal, US Trade Representative Robert Lighthizer refused it.It is a telling moment. It shows that Trump cares more about removing restrictions on America's freedom to make choices than on achieving his specific trade goals. The personal lesson about Trump is that he genuinely believes NAFTA undermines America's ability to negotiate effectively with its trade partners. Indeed, this is precisely what galls him about all these trade agreements.Far from making things fair, he believes “rules-based” trade robs America of what he sees as its greatest asset: its ability to use its size, wealth, power, and prestige to advance its interests in negotiations like these. Instead, these agreements shackle it.This is also why he hates multilateral institutions, from NAFTA and the WTO to NATO and the G7: they create equality among players who, in his view, are not equals. Why, he wonders, is that in America's interest?What Canadians need to see here is that Trump's plan to Make America Great Again is the antithesis of the rules-based agreements we are working toward. He is not aiming to create a fairer, more stable international order. His goal is to rebuild American industry – whatever the cost to Canada, Mexico, or the EU.Indeed, Trump has said repeatedly that he'd prefer to walk away from NAFTA and start over. In his view, that's the fastest and simplest way for America to regain the leverage he believes it's lost.However, if he feels he must reform the agreement – as he has been trying to do – he seems determined to explode any expectation that America will continue to submit to international rules of fair play. Tariffs are the lynchpin in this effort. Will he use them on the auto sector? Very possibly.As for the skeptics, they not only think Trump is bluffing, but that he will settle down after the midterms and make some concessions. I just don't see it – at least, not if the Republicans keep the House. If they do, Trump will emerge as the undisputed owner of the party. I think he will become relentless – and insufferable – in the pursuit of his goal.What if Democrats take the House? Hopefully, they will continue to treat rules-based trade as an integral part of their commitment to multilateral institutions, such as NATO, the UN and the G7 and provide a much-needed counterbalance to Trump.Another view, however, is that they have protectionist sentiments of their own and might be even more supportive of tariffs than Republicans. As Foreign Affairs Minister Chrystia Freeland often says, we should prepare for the worst and hope for the best.Dr. Don Lenihan is an internationally recognized expert on public engagement and Open Government. He is currently advising The Ottawa Hospital on an engagement plan to develop its new Civic Campus – a $2 billion, 10-year project. He also co-chairs the Open Government Partnership's Practice Group on Open Dialogue and Deliberation. Don can be reached at: [email protected] or follow him on Twitter at: @DonLenihan