President Trump has consistently shown hostility towards the European Union. He has repeatedly asserted that the bloc was established to “screw” America, has threatened to impose significant tariffs on its cars, and this week imposed global steel and aluminum levies expected to impact about $28 billion worth of exports from the bloc.

For months, E.U. officials hoped they could change the American president’s stance, avoiding a costly trade war. They attempted to appease the administration with measures such as increased European purchasing of U.S. natural gas, while working towards a deal.

It is now clear that the situation won’t be so simple.

When American tariffs on steel, aluminum, and products that use those metals took effect last Wednesday, Europe responded by announcing a comprehensive package of retaliatory tariffs. The first wave is set to take effect on April 1, imposing tariffs as high as 50 percent on products such as Harley Davidson motorcycles and Kentucky bourbon. A second wave will target farm products and industrial goods that are significant to Republican districts in mid-April.

European officials made it clear they were not eager to take such an aggressive stance; they wanted to negotiate and still do.

“But you need both hands to clap,” stated Maros Sefcovic, the European Commission’s trade minister, on Wednesday. “The tariffs’ disruption can be avoided if the U.S. administration accepts our extended hand and works with us to strike a deal.”

Europe is facing a difficult reality. It is uncertain to many European officials exactly what Mr. Trump wants. Tariffs are sometimes explained by administration officials as an effort to level the playing field, but they are also cited as a tool for raising funds for U.S. coffers to finance tax cuts, or as a means to punish the E.U. for its regulation of technology companies.

Mr. Trump has stated that Europe has “not been fair” in its trading practices. On average, Europe’s tariffs are slightly higher than U.S. tariffs; however, specific products, such as cars, face notably higher tariffs when shipped to Europe.

Mr. Trump has also taken issue with how Europe and other nations tax producers and has suggested that future U.S. tariffs will also respond to these policies. Some of the tariff rates he has floated would be far higher than those he criticizes in Europe.

“We’re going to take back our wealth, and we’re going to take back a lot of the companies that left,” Mr. Trump stated on Wednesday. He stated that U.S. tariffs would mirror foreign approaches, though there would be “some cases where they’re a little bit beyond reciprocal”.

Nor has the Trump administration appeared keen on negotiating. Mr. Sefcovic visited Washington in February, but he has admitted that he made little progress. President Trump has not spoken individually with Ursula von der Leyen, the European Commission president, since taking office.

Without a clear understanding of what Mr. Trump wants and without trusted intermediaries within the administration, it is challenging to figure out how to strike a deal that will prevent hurt for consumers and companies.

“It doesn’t feel very transactional, it feels almost imperial,” stated Penny Naas, a trade expert at the German Marshall Fund. “It’s not a give and take — it’s a ‘you give.’”

That is why the E.U. is now highlighting that it can hit back if forced and that there will be more measures if the Trump administration goes ahead with the additional tariffs it has threatened. The bloc aims to keep its measures proportionate to those of the U.S., trying to avoid escalating the conflict.

But Europe has also been preparing for months for the possibility of a full-blown trade war, even if it hoped to avoid one.

Olof Gill, a European Commission spokesman, stated during a news conference on Wednesday, “If they move ahead with those, we will respond swiftly and forcefully, as we have today. We have been preparing assiduously for all outcomes. We showed today that we can respond swiftly, firmly, and proportionately.”

The question is what might come next.

Mr. Trump has promised additional tariffs on European goods, including so-called “reciprocal tariffs” that could come as soon as April 2. He’s also talked about significantly raising tariffs for specific products, like cars.

“It’ll be 25 percent, generally speaking, and that will be on cars and all other things,” Mr. Trump stated in late-February Oval Office comments. “The European Union was formed in order to screw the United States. That’s the purpose of it, and they’ve done a good job of it, but now I’m president.”

European officials have stated that if things worsen, they could use a new anti-coercion instrument enabling them to impose tariffs or market limitations on service companies. This could affect technology firms like Google.

While Europe sells more physical goods to the U.S. than it buys, it runs a significant deficit with the U.S. in technology and other services — largely because Europeans are a significant market for social media and other internet-based companies.

Mr. Sefcovic has listed the anti-coercion instrument as a “hypothetical option” to “protect” the European market from outside interference, and other European leaders have been vocal about the possibility of using it specifically against the U.S.

But as Europe does not want to exacerbate the trade war, targeting American technology firms is seen as a tool for more extreme circumstances.

“It’s more the nuclear option,” said Carsten Brzeski, a global economist for ING Research.

For now, European officials are hoping that the threat of retaliatory tariffs will be enough to bring America towards the negotiating table. The measures are expected to impact products that are crucial in Republican strongholds: Kentucky bourbon, Louisiana soybeans.

As workers and companies face grim predictions, the theory is that they will pressure their political contacts and urge them to negotiate.

The spirits industry — which will be severely hit by the 50 percent tariffs on whiskey — has already raised concerns. The industry was significantly affected by an earlier and less severe version of the retaliatory tariffs during Mr. Trump’s first administration.

“Reimposing these debilitating tariffs at a time when the spirits industry continues to experience a slowdown” would “further restrict growth and negatively impact distillers and farmers across the country,” stated Chris Swonger, the chief executive of the Distilled Spirits Council, in a statement on Wednesday.

Political instability is already causing pain for some American companies. Tesla’s sales in Germany plummeted in February and have declined throughout Europe, highlighting anger against Elon Musk, the company’s CEO and close ally of Mr. Trump.

However, the administration has shown willingness to accept some economic pain in pursuit of its long-term trade objectives — which involve nothing short of rewriting global trade rules.

“There is a transition period because what we are doing is very big,” Mr. Trump stated in a Fox News interview on Sunday.

To Europe, a world where Mr. Trump is bent on reorganizing the global order is a more dangerous one. The unfolding conflict risks permanently undermining its most vital trading relationship, which it has long perceived as mutually beneficial, while damaging its close alliance with the United States.

“There are no two economies in the world as integrated as the United States and Europe,” Ms. Naas said. “Decoupling is not really an option at this point, so now we’re going to be stuck in this tariff paradox.”

Ana Swanson contributed reporting.