Oil prices jumped at the market open on Monday after U.S. President Donald Trump imposes tariffs on Canada, Mexico and China, raising fears of a trade war and disruption in crude supply from two of the United States' biggest suppliers.

"Despite the 'energy emergency' claims, the US is producing energy in record quantities," JPMorgan Asset Management wrote.

All else equal, this would increase gasoline prices, which in most of the country have averaged $3 per gallon for the past year amid historically low levels of petroleum inventories (see chart). But Trump wants lower gasoline prices, which is why if the oil tariffs come at all, they will likely start slowly.