This week, western leaders gathered in Lithuania for a NATO Summit.

NATO – the North Atlantic Treaty Organisation – is not a body we have had much cause to think about until recently. Since Russia’s invasion of Ukraine, it has taken on a new significance.

This week, I will take a closer look at the dilemma NATO faces over Ukraine and what it could tell us about similar dilemmas faced by Australia in future.

In 1945, after two wars in quick succession, Europe was in tatters.

Over the next few years, two new institutions would shape its recovery: NATO and the European Union. Both can be thought of as ‘clubs’, but of very different kinds: the EU is ‘peace club’ and NATO is ‘war club'.

War club came first. NATO began as a security alliance against Russia’s Soviet Union. Its main advantage was that it included (and was in fact initiated by) the United States.

Importantly, NATO members agreed to defend one another in the event of an attack – which really meant the U.S. would defend Western Europe if Russia attacked.

The U.S. backed this up with a massive program of economic assistance to get the European countries back on their feet. It meant that, in the U.S.-Russia Cold War that would dominate the rest of the century, Western Europe would be firmly in the U.S. corner.

NATO’s purpose was to protect Western Europe against an external threat. The EU was all about protecting Western Europe from itself.

After fighting against one another in two world wars, the European powers were determined to strengthen their ties to one another to make future wars “not merely unthinkable, but materially impossible”.

That spirit of co-operation gave birth to the EU. While it has not been without difficulty, it has certainly achieved peace in Western Europe. A war between the old enemies like France and Germany did become “unthinkable”, and many EU members enjoyed decades of economic prosperity.

In light of this success, European countries who at first did not join the two clubs soon wanted to do so.

In particular, this happened in the 1990s and 2000s with the countries of Eastern Europe, which were formed when the Soviet Union crumbled. Each of NATO and the EU has added about a dozen new Eastern European members since the year 2000.

One country, though, has had great difficulty getting in: Ukraine.

Ukraine has wanted to join Europe’s two clubs for decades, but has made minimal progress. Why? It’s a controversial question, and one which clearly frustrated Ukrainian President Volodymyr Zelenskyy this week when another NATO summit passed without clarity.

There are many reasons, but one very obvious one: Russia. Under President Vladimir Putin, Russia has fiercely opposed Ukraine’s bids to join Europe and has long threatened to retaliate if the NATO bid succeeded.

At first, European leaders delayed Ukraine’s bid to avoid provoking Russia. In the end, Russia acted anyway, invading the Ukrainian region of Crimea in 2014 and the whole country in 2022.

That invasion has added another difficult dimension: adding Ukraine to NATO would mean other NATO members are bound to defend it. In theory, that would mean French, German, British and American troops on the ground, fighting against Russia.

NATO countries (and Australia) have been happy to supply weapons to Ukraine, but supplying their own soldiers has been a different story. As U.S. President Joe Biden put it last year, “when Americans and Russia start shooting at one another… we’re in a very different world than we’ve ever been.”

There is no sign the West’s attitude to joining the Ukraine war will change.

However, there are signs it might be a different story if a similar scenario in a different part of the world played out: China invading Taiwan, the self-governing island it regards as its own territory.

Even though the U.S. is not required, by NATO or any other agreement, to defend Taiwan, Biden last year explicitly promised to send in U.S. troops if China attacked Taiwan.

This would pose a very difficult question for Australia. According to a recent survey by the Lowy Institute, most Australians would not support getting directly involved: 76% would support sanctions on China and 64% would support military supplies for Taiwan, but only 42% would favour the use of Australian troops.

For now, the question is hypothetical. The Australian Government is keen to emphasise it wants to keep it that way.