Can you smell the whiff of smoke? You surely can. But the gunfire? Not yet. But it must start soon if the battle has any chance of success.

President Donald Trump has to be faced down. Not only because of his sabotage of the Iran nuclear deal but also because of his attack on Europe’s export of steel and aluminum which breaks all the rules on tariffs set by the World Trade Organisation.

This man should not be allowed to get away with his gross disturbance of the world political and economic order.

Donald Tusk, the President of the Council of the European Union, said boldly last week, “Who needs enemies when you have friends like this?”

Who indeed? Trump is, as David Goodhart wrote in Foreign Affairs, “a living fossil, the sort of ‘ugly American’ common enough in earlier eras”.

Trump is leading America into a dark tunnel where there is no sunlight and no daylight at the end.

His unilateral ending of the Iran nuclear agreement could easily lead to war between Israel and Iran, between Iran and Saudi Arabia and even between the US and Iran. The Middle East, already devastated by wars that the US and the UK started, will become a moonscape of destruction.

Iran, instead of being just an antagonist of the US will become an enemy, strong enough to give the US a large and regular dose of political and military pain.

Does America, even many of those who voted for Trump, want to confront Iran? The polls say “no” by a good margin.

For nearly 80 years America and Europe have for most of the time run in a three-legged race. This had disadvantages, but most of the two electorates have wanted it this way, and still do. Trump doesn’t. His irrationality can only be explained by his determination to undo all the good things Barack Obama did.

This is not a good enough reason to break up the JCPOA nuclear deal with Iran that Europe, Russia and China so value. Europe must call a halt to this.

Retaliation is the only way. Sanctions, the weapon that brought Iran and white South Africa to the negotiating table, must be introduced against the US.

Europe is both strong enough to do this and strong enough to go for the long haul. Europe has 500 million consumers compared with the US’s 300 million. It will also have the quiet support of Russia and China.

Politically Europe is more than ready.

Before Trump announced earlier this month that he was abrogating the Iran deal, polls in Germany and France showed how popular Obama was and how unpopular is Trump. Days after Trump’s election a survey found that 75% of the French held a negative opinion of him. The then president, Francois Hollande, said Trump’s “excesses” made him want to “throw up”.

A survey reported that 92% of Germans disapprove of Trump. According to a Pew survey 25% of Germans trust Putin compared with 11% who trust Trump.

Economically, Germany has the power to face down Trump, especially when supported by the rest of the EU. The US only buys 9% of German’s exports. The EU overwhelmingly trades with itself. On the other side of the coin, German companies employ 700,000 people in the US.

Europe’s squeeze should probably begin with sport, just as President Jimmy Carter did at the time of the Soviet invasion of Afghanistan. The US withdrew its contingent from the Olympics in Moscow. It badly upset the American athletes who had trained for years. But it was broadly popular in America.

Sport boycotts quickly call the populace’s attention. At least half of Americans have only a crude idea why the Iran nuclear agreement is so important. So to hit the US with a boycott of US tennis matches and American players in Europe will hurt.

So it will with rowing at Henley and ice hockey in Sweden. It is likely that Russia, also a signatory of the Iran agreement, could be persuaded to ban the US from the football World Cup in Moscow next month.

Germany and other European investors in America should be made to withdraw some of their investments and lay off American workers (with good termination payments). New investment should be halted.

European car, drug, machinery and high tech manufacturers should be given government direction and help to invest more in Canada, Japan, China, India, South East Asia, Africa and Latin America, all of which – apart from the last – have booming markets.

The EU (and Russia) should rely more on themselves for rocket development and space exploration.

Where possible trade with Iran should be sheltered from US sanctions.

The list can easily be made longer. I doubt if Trump will be able for long to resist the pressure to change his mind from an electorate already turning against him.