Sydney, As NATO counts down to its annual summit in Turkey in July, the alliance is facing perhaps the biggest challenge in its history – what a potential future without the United States, or US security guarantees, would look like.
In recent weeks, the Trump administration has taken a series of steps widely interpreted in European capitals as retaliation for allies' reluctance to more strongly support the US position in the Iran war.
Europe was already uneasy about Washington's broader strategic intentions.
Increasingly, NATO allies are realising they can no longer depend on the United States for their security and will have to shoulder far greater responsibility themselves.
NATO 3.0======US President Donald Trump's narrow understanding of the value of alliances has long been known. Now, his vision for a new NATO is coming into view.
At a NATO defence minister meeting in February, the US under secretary of defence for policy, Elbridge Colby, introduced the idea of "NATO 3.0". This would entail Europeans assuming a much larger role in conventional deterrence.
The US, meanwhile, would prioritise strategic competition with China and supporting European security more selectively and from greater distance.
A focus on collective defence==================One thing is certain: one single country won't simply replace the United States as alliance leader.
No European power possesses the capabilities, resources or political legitimacy to fill that role alone.
Instead, leadership will likely come from the most capable states acting together.
The new reality=========The "new NATO" is by no means a settled compact.
It is an alliance caught between competing visions, profoundly uncertain political commitments from erstwhile supporters, and unresolved strategic questions.
Europe is moving towards greater responsibility for its security, but without a clear consensus on what greater strategic autonomy ultimately means.
