US President Donald Trump, to the alarm of US trading partners and economists, has been making good on his campaign pledges to slap punitive tariffs on countries he accuses of cheating American workers.
His latest move is a threat to remove the US from the World Trade Organization. Here is a summary of the ongoing conflicts:
After weeks of apparently fruitless negotiations, the United States imposed 25% tariffs on approximately $34 billion of Chinese products in July, sparking an immediate dollar-for-dollar response from Beijing.
The two countries traded blows during the summer, this time hitting $16 billion worth of goods from each other with more punitive customs taxes.
President Trump has reportedly threatened to slap import taxes on $200 billion in Chinese goods while China has vowed to hit back with tariffs on $60 billion in American goods - a smaller amount that highlights Beijing's limited ability to retaliate since it imports much less than it exports.
China has filed a complaint in the WTO against the US actions. Despite Mr Trump's sharp criticism of the WTO, the US has in turn filed a complaint against the retaliation by China and others.
After several months of threats, Mr Trump imposed tariffs of 25% on steel and 10% on aluminium from the EU, Canada and Mexico in June.
Mr Trump has said the European Union is "possibly almost as bad as China" when it comes to trade, as a raft of retaliatory tariffs from Brussels came into effect on 22 June.
From blue jeans to motorbikes and whiskey, the EU's hit-list of products targeted the most emblematic of American exports.
Mr Trump has also threatened to impose punitive levies on imported cars, something Germany's powerful car industry particularly fears.
But European Commission President Jean-Claude Juncker and Mr Trump on 25 July announced a plan to defuse the row, with Washington backing off the car tariffs against Europe, at least for now.
Canada and Mexico
Canada and Mexico, members of the North American Free Trade Agreement (NAFTA) with the US, have imposed their own counter-tariffs on US goods after Washington's steel and aluminium duties took effect.
Mr Trump and Canadian Prime Minister Justin Trudeau traded barbs over the steel tariffs at a farcical summit of the G7 countries in June.
Those tariffs were imposed after Mr Trump came to office demanding an overhaul of the "terrible" NAFTA deal.
Mr Trump has threatened to leave Canada on the sidelines since announcing a breakthrough with Mexico on Monday.
However, but the US president and Canadian Prime Minister Justin Trudeau have both expressed optimism a new deal is close.
Japan is another target of Mr Trump's steel tariffs, which Tokyo calls "extremely deplorable".
Japan has informed the WTO that it plans to impose retaliatory measures on US goods to the tune of 50 billion yen (€395m).
It also wants an exemption from the threatened US duties on car imports, which represent a major threat to its car industry as well as Germany's.
Mr Trump announced in May he was abandoning the 2015 nuclear deal with Iran and reimposing sanctions in two phases, with the second targeting the country's vital oil and gas sector.
That entails the potential for huge penalties against those who trade with Iran, including European energy firms and carmakers.
But many of its bigger companies have already pulled out of the country before their investments could bear fruit, including Total, Daimler, Siemens and Peugeot.
Igniting a secondary skirmish, Mr Trump said that he had doubled steel and aluminum tariffs on NATO ally Turkey amid a row over an American pastor held for two years on terror charges.
The Twitter announcement on 10 August caused the Turkish lira to crash nearly 20%, and prompted President Recep Tayyip Erdogan to claim Turkey was victim of a "political plot" and an "economic war".
Turkey has in turn hiked tariffs on imports of several US products such as rice, alcohol, leaf tobacco, cosmetics and cars.