Imposing punitive tariffs on countries with high trade surpluses with the United States has been at the heart of US President Donald Trump's economic policy.

Trump has lived up to his campaign pledges to resume his hardball trade diplomacy.

But analysts say trade imbalances can sometimes be the result of US policy itself.

A trade deficit occurs when a country's imports exceed its exports to another country. The balance is usually calculated on trade of goods such as cars, electronics, farm products or oil and gas, among other things.

International comparisons usually focus on goods but some analysts say trade in services -- such as financial systems, transports, tourism or communications services -- should also be taken into account to get the full picture.

The United States, for instance, has a large trade deficit with many of its partners when just considering goods, but once services are taken into account the overall imbalance is less.

"Politicians are obsessed with the material nature of physical goods," said Niclas Poitiers, a research fellow at Brussels' think tank........

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