NATO allies in Europe are becoming increasingly concerned that the United States, the backbone of the alliance, may be leaving after nearly 80 years.

According to an editorial in The Economist, President Donald J. Trump is seriously weighing that option.

In recent years, NATO has focused its attention on the conflict between Russia and Ukraine, now in its fourth year. It has also not focused more resourced on aiding the United States in its war with Iran, now in its fifth week.

They have supplied billions of dollars in weaponry to the Ukrainian side, and have attempted to halt Russia’s advance into the country.

However, the stalemate has angered Washington, who argue that it is a senseless war on both sides and needs to be brought to a swift conclusion.

The Ukraine war is the longest and deadliest conflict in Europe since World War II.