Freedom of navigation — the legal principle that states ships from any country have the right to sail freely in international waters — is under attack.

It has been for some time.

But a confluence of geopolitical shifts, security threats and an accelerating frequency of legal assaults are finally starting to erode a fundamental principle of the law of the sea and a pillar of modern international law.

For the first time since the Cold War, maritime trade lanes have become contested zones and the rules-based order that shipping has previously relied on to protect it has started to disintegrate.

And that threat is coming from multiple different vectors.

A good starting point for that is what’s happening in the Baltic right now.

What Denmark and the Nordic-Baltic states have said is that they would take “coordinated steps to disrupt and deter Russia’s shadow fleet”. While the language is deliberately vague, this amounts to politely requesting details of suspect ships’ insurance. If they don’t comply they risk being sanctioned, but so far none of the states are suggesting they will go further than that. For now.

Geopolitical tensions are deepening and global maritime trade is being caught in the crossfire, both literally and figuratively. Trade lanes on the oceans are contested zones for the first time since the Cold War.

The question is whether there is sufficient energy left amongst those backing the crumbling rules-based order to defend it.