Those nation states, like Ukraine, that were part of the old Soviet Union obviously want to be part of NATO to safeguard themselves from Russia, while Russia has security concerns about the continuing expansion of NATO and its encroachment on Russia's borders.

Both parties have valid historical reasons for being concerned about being invaded or attacked. Russia lost 30 million of its population during the Second World War, while perhaps as many as 10 million Ukrainians died during the 72-year Russia-dominated Soviet era.

[Russian leader Stalin tried to eliminate the intelligentsia of Ukraine, forcibly deported Ukrainian Kulaks who opposed his collectivisation policies, and orchestrated deliberate mass starvation of Ukrainians throughout the Soviet Empire.]

In 2019 I visited an old abandoned Russian military base near Chernobyl in Ukraine, located in the nuclear exclusion zone. Because of it being in a closed area, it was largely intact. The most impressive feature was the over-the-horizon radar that was 700 metres long and 150 metres high. Its purpose was to provide early warning of incoming American missiles headed for targets in Russia. In the base's command centre, there were pictures of all the missiles in the American inventory pre-1989, and details of their characteristics.

Russia is very concerned about the expansion of NATO and particularly about Ukraine becoming part of NATO, with the possibility of American missiles being deployed to Ukraine.

Russia's security concerns are better understood when compared with how the US itself would react to neighbouring Mexico becoming part of a security pact dominated by Russia, with the possibility of Russian missiles being deployed to Mexico. We all know how the Kennedy Administration reacted in 1962 to Khrushchev's Russia deploying long-range missiles to nearby Cuba.

NATO was created in 1949, and since then the security alliance has increased from the original 12 countries to 30. NATO currently recognizes Bosnia, Georgia, and Ukraine as aspiring members. An additional 20 countries participate in NATO's "Partnership for Peace" program, with 15 other countries involved in institutionalised dialogue programs.

Australia is referred to by NATO as one of its "partners across the globe", with a joint agreement to work together on crisis and conflict management, post-conflict situations, reconstruction, facilitating humanitarian assistance, and disaster relief.

Russia opposes any NATO expansion, regarding it as inconsistent with the informal understandings between Soviet leader Mikhail Gorbachev and European and US negotiators that allowed for peaceful German reunification.

Despite its "North Atlantic" title, NATO - under pressure from the US, has since engaged in several out-of-area commitments, such as its former International Security Assistance Force in Afghanistan, and military support activities in Iraq, the Gulf of Aden and Libya.

Moscow sees US-dominated NATO expansion as a continuation of the US's Cold War intent to surround and isolate Russia. From a Russian perspective, NATO not only poses a growing military threat, but also limits Russia's external strategic options in the Mediterranean and Middle East, particularly given the economic limits on what it can afford to do.

A June 2016 Levada poll found that 68 percent of Russians think that NATO troops in the Baltic states and Poland - former Eastern bloc countries bordering Russia - are a threat to Russia.

Despite Australian concerns about Russia, it is an economic minnow compared to its potential adversaries. Russia's GDP is only 1.5 trillion US dollars, compared to Australia's 1.3 and Germany's 3.8. Russia manages to be impressive militarily by sacrificing 4.3 per cent of its GDP to defence. (Australia spends slightly more than 2 per cent.) To underline just how small Russia's economy is, the GDP of the US is $21 trillion.

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The combined military spending of NATO members in 2020 constituted over 57 per cent of the global total of military expenditure, with the US accounting for two thirds of that amount. Russia's military expenditure is only 3.1 per cent of global expenditure.

There is scope for miscalculation - as there is for accommodation, on both sides. President Putin faces the problem that if he fails to stop Ukraine from joining NATO, he and Russia will be seen as weak, and that will encourage others, like China, to be more assertive in their territorial disputes with Russia. It might also encourage other former members of the Soviet bloc to join NATO.

The US and NATO need to assess carefully what they can achieve strategically without pushing Putin beyond a point of no return. Any conflict in Ukraine - assuming it didn't go nuclear, would be counterproductive. It would likely result in Russia occupying more of Ukraine and becoming a more dangerous adversary, especially if it's isolated economically through Western sanctions.