The outlook for Europe’s economy has been disappointing.

Last week — after Donald J. Trump’s presidential election — it got worse.

Deep uncertainty about the Trump administration’s policies on trade, technology, Ukraine, climate change and more is expected to chill investment and hamstring growth. The launch of a possible tariff war by the United States, the biggest trading partner and closest ally of the European Union and Britain, would hammer major industries like automobiles, pharmaceuticals and machinery.

And the need to raise military spending because of doubts about America’s guarantees in Europe would further strain national budgets and increase deficits.

In addition, the president-elect’s more confrontational attitude toward China could pressure Europe to pick sides or face retribution.

“Europe’s worst economic nightmare has come true,” said Carsten Brzeski, chief economist at the Dutch bank ING. The developments, he warned, could push the eurozone into “a full-blown recession” next year.

With political turmoil in Germany and France, Europe’s two largest economies, this latest blow could hardly come at a worse time.