The North Atlantic Treaty Organization was conceived to "keep the Soviet Union out, the Americans in and the Germans down," Britain's Lord Hastings Ismay, the first secretary-general of NATO, once said. That was just after World War II and at a time when the Soviet Union controlled the entire eastern half of Europe — including East Germany — and the Americans were again considering whether they should leave Europe to its own devices, which would probably have meant even greater Soviet influence.

Germany was not kept down for long, at least not the western part, and in 1955 the Federal Republic itself joined NATO; the East, the German Democratic Republic, joined the Soviet-controlled Warsaw Pact.

The Cold War and its mutual deterrence lasted just over 40 years. The situation was tense, but it was stable. "Our first priority is to maintain a strong and healthy partnership between North America and Europe, for this is the foundation on which the cause of freedom so crucially depends," US President Ronald Reagan said in 1988, as disarmament talks with the Soviet Union continued. "We will never sacrifice the interests of this partnership in any agreement with the Soviet Union."

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New conflicts

The situation changed dramatically in 1989 and '90. The Soviet Union fell apart, and the allied powers of World War II agreed to the reunification of Germany, a NATO member. The upheaval in Europe also meant that, within the span of a decade and a half, former Warsaw Pact countries including Poland, Romania and the Baltic states had joined NATO.

Now, 70 years after NATO was founded on April 4, 1949, the situation resembles the Cold War era once again.

Russian officials feel threatened by NATO's eastward expansion and are strengthening the country's military. This has slowed down the alliance's further expansion. Georgia and Ukraine, for instance, have little hope of joining at the moment because NATO leaders want to avoid more conflict.

NATO is already involved in plenty of conflicts. Since the 1990s, the alliance has increasingly intervened outside its territory worldwide. Germany, with its expansionist Nazi past, initially faced heated debate for engaging in operations abroad, but the country is now involved in quite a few foreign missions, including in the Balkans and Afghanistan.

In its 70-year history, NATO has only once invoked what is known as casus foederis, the situation in which the terms of an alliance come into play and all members are called upon to collectively defend a member under attack: after the terrorist attacks of September 11, 2001, in the United States. However, a fierce dispute broke out over the consequences of that decision, and NATO's divisions have deepened since.

The pressure on NATO from the United States has increased since Donald Trump assumed the US presidency in 2017. He has repeatedly questioned the significance of NATO, as well as the collective obligation to provide assistance. In 2018, Trump asked why the United States should defend a smaller member country like Montenegro and risk a "third world war." He also said the US would only protect the countries that paid their full dues. Trump has repeatedly accused Germany, in particular, of spending far too little on defense. At the 2018 NATO summit, Trump toned down his rhetoric somewhat while maintaining his position that the United States was being exploited. "We're paying for far too much of NATO," he said. "NATO is very important. But NATO is helping Europe more than it's helping us."

At that same summit, Chancellor Angela Merkel acknowledged that Germany had a great historical debt to NATO, but she also said her country had done a lot for the alliance. "We are the second-largest provider of troops, we put most of our military capabilities at the service of NATO, and we are to this very day very much involved in Afghanistan, and in doing so we also represent US interests," she said.

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'Our military capabilities'

At their 2014 summit, the leaders of NATO countries agreed to commit 2 percent of their national GDP to defense spending by 2024. In 2018, the US spent 3.39 percent, but just a few European NATO members had reached the 2 percent target. Germany spent just 1.23 percent. The most recent budget also misses the target by miles. Merkel has promised 1.5 percent by 2024; Trump continues to demand "at least" 2 percent. The Social Democrats (SPD), the junior partners in Merkel's governing coalition, have put the brakes on defense spending. SPD foreign policy spokesman Nils Schmid has warned of a fetishization of the 2 percent threshold. "What matters is that we increase our military capabilities, and that is what we are doing," he told DW. The dispute is far from over.

 "It is not written in stone that the trans-Atlantic bond will survive forever," NATO Secretary-General Jens Stoltenberg said in speech in 2018.

But Stoltenberg also expressed optimism. "We have had differences before, and the lesson of history is that we overcome these differences every time," he said, adding that, in the end, NATO members agree that North America and its partners in Europe are safer together.

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