President Donald Trump is complaining about Canadian trade practices while threatening some as-yet-undefined international tax that has revived fears he might be contemplating new American import penalties.

The U.S. president made the remarks at the White House on Monday while unveiling a long-awaited infrastructure plan. During a lengthy session with reporters, he complained about countries considered allies of the U.S.

He mentioned one directly to America鈥檚 north.

鈥淐anada does not treat us right in terms of the farming and the crossing the borders,鈥� Trump said.

鈥淲e cannot continue to be taken advantage of by other countries.鈥�

It鈥檚 unclear what he was referring to. In the past, he has complained about Canada鈥檚 dairy controls and softwood lumber. Administration officials have also expressed anger over Canada鈥檚 wide-ranging attack at the World Trade Organization on the U.S. system for imposing duties.

Meanwhile, the White House downplayed the tax threat Monday and various U.S. media outlets said there was nothing imminent.

Trump did promise more clarity on a new tax. More details could be coming this week, he suggested.

鈥淲e are going to charge countries outside of our country 鈥� countries that take advantage of the United States,鈥� Trump said. 鈥淪ome of them are so-called allies but they are not allies on trade. 鈥� So we鈥檙e going to be doing very much a reciprocal tax and you鈥檒l be hearing about that during the week and the coming months.鈥�

It鈥檚 unclear what type of tax he鈥檚 referring to. Earlier this year, the administration dropped the idea of a border-adjustment tax in its since-passed fiscal reform, because of widespread opposition on Capitol Hill.

The confusion was compounded by several factors:

鈥擨n the U.S., Congress sets tax rates 鈥� not the president. And the Congress, which just completed a major tax reform, has shown little inclination to hike taxes.

鈥擳ariff rates, meanwhile, are negotiated at the WTO.

鈥擳he idea wasn鈥檛 even mentioned in the White House鈥檚 2018 budget proposal 鈥� which was released Monday.

The most specific clue Trump offered involved motorycles.

He complained that the U.S. brings in products tariff-free and other countries sometimes charge more than 50 per cent tariffs on the same product: 鈥淗arley-Davidson. They鈥檙e treated very unfairly in various countries. You know the countries I鈥檓 talking about,鈥� Trump said. 鈥淪o we鈥檙e going to be doing very much a reciprocal tax.鈥�

Those motorcycle tariffs are highest in Asia 鈥� they don鈥檛 exist in North America.

Several trade experts contacted Monday confessed to some confusion about what the president was threatening. Dan Ikenson of the Cato Institute said the only action he could think of might violate international trade law.

It involves a rarely used retaliatory measure from a 1974 U.S. trade law.

鈥淐ould be anything, but nothing he could do, while remaining true to the trade rules,鈥� Ikenson said.

鈥淧resumably, he could invoke Section 301 (of the 1974 U.S. Trade Act) and threaten to impose taxes to mitigate, countervail, reverse foreign practices that he finds unfair. (That) could pass muster with U.S. law, but not WTO rules.鈥�

Alexander Panetta, The Canadian Press

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