The first shot has been fired in a transatlantic trade war that opens up yet another front between the European Union and the United States after their increasingly diverging views on Russia's war in Ukraine and the security architecture of the Continent.

Since early February, it was known Washington would impose a 25 percent tariff on European steel and aluminum imports starting on March 12.

U.S. President Donald Trump is a vocal critic of the American trade deficit in goods -- not only with Europe -- and believes tariffs are a way to bring investments and jobs back to America.

Brussels has been bracing itself for this moment ever since Donald Trump reentered the White House in January, which is why countermeasures were immediately announced on March 12. The US move targets trade worth $28 billion (25.6 billion euros), and the European Union hit back with a package of measures that will total 26 billon euros rolled out in two phases.

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The first, coming on April 1, hits classic "Americana" products such as bourbon, jeans, and Harley-Davidson motorcycles and is worth 8 billion euros. This is essentially a "snap back measure" from the first Trump term, when the United States and the EU were embroiled in a similar trade spat, and doesn't require the approval of EU member states as trade is primarily the responsibility of the European Commission.

The second batch of tariffs, proposed to come into force on April 13, however, needs a qualified majority of EU member states. This one targets goods like agricultural products, textiles, home appliances and plastics, and totals 18 billion euros.

The early belief among diplomats whom RFE/RL have spoken to is that this majority very much exists as the bloc has grown increasingly exasperated with the US administration. But it's shaping up to be a prolonged war in which Europe has more to lose than the United States.

Is The EU Ready For A Trade War?

The figures tell the whole picture. Last year, the United States was comfortably the European Union's largest partner for the export of goods with 20.6 percent going across the Atlantic -- over $600 billion worth, in fact. However, the EU "only" imported $370 billion from the United States in that same period. This is what annoys Trump -- and that makes the EU vulnerable in this fight.

The EU is very much a free trade champion in a league of growing protectionism. And while the club has struck a recent free trade deal with a group of countries in Latin America and is courting growing economic giants like India, the transatlantic trade simply is too lucrative.

Chart: Average U.S. Tariffs, 1891-2021

Big European exporters such as Germany, Italy, and the Netherlands -- all of which are grappling with little or no economic growth -- are painfully aware of this. The EU appears united for now, but the longer this goes on, the more individual member states will pressure Brussels to strike a deal with Washington.

When European Commission President Ursula von der Leyen announced the countermeasures early on March 12, she immediately highlighted that "we will always remain open to negotiations."

The hope in Brussels now centers on two things: firstly, that Washington will be willing to lift the measures, at least for a while, just like it has done repeatedly with Canada and Mexico in recent months. And, perhaps, more importantly, that the situation won't escalate further and become a bargaining chip in other political issues such as the war in Ukraine and the security of European countries that still depend on American goodwill.