A resurgent Russia, another Japan and an ever-dangerous China.
These geopolitical challenges may be changing the nature of warfare.
UK Prime Minister Theresa May has said these circumstances force her country to develop a “plan B” for European defence if the US does not step up.
That plan is going out for public consultation in the second half of this year.
It has all the hallmarks of a basic new idea: an EU standing army.
It includes some of the obvious ingredients that voters demanded when they voted for a second referendum on Brexit – a national investment plan to help build new defence equipment.
Read more: The EU sees cooperation, not military cuts, as its Brexit success story
Those plans include buying tanks for all member states.
A significant new defence headquarters for NATO allies France and Germany was also promised, with a budget to “streamline” defence work.
The eurozone joint defence budget will be doubled to €50bn by 2021 and its call for funds from the EU budget is enhanced to €20bn for the period 2021-2027.
For the moment, this is just a proposal with no money.
But several things about it are worth keeping in mind:
The current EU budget is only about €200bn – barely enough to buy a decent fighter jet.
The EU defence plan contains no mention of plans to raise that budget.
And most important, Mr Trump’s withdrawal from the Iran nuclear deal has again highlighted the US commitment to Nato.
In retaliation for the US abandonment of a nuclear agreement, Iran is attacking US forces in Afghanistan – a huge row over American special forces.
US special forces are both fighting and training alongside their European allies.
One idea under consideration in the EU defence plan is that the US military could carry out some of this training and training.
All of this comes at a time when EU member states are struggling to provide their troops with sufficient ammunition, vehicles and equipment.
The fear is that if the UK is sidelined after it leaves the EU, they won’t have enough soldiers on the ground to operate effectively against the advanced technology deployed by Moscow, China and elsewhere.
It is not a perfect analogy, but in March 2017, without warning, the US government took out part of the National Security Agency (NSA)’s Cold War infrastructure which had been under permanent summer supervision.
The hacking room was an antiquated facility running on emergency cables.
There was talk of an “attack room” being installed on American soil and a detailed plan was ready to create one in the UK.
But the UK quietly pulled out of the facility, fearful it would be used to spy on its security services.
That incident was a stark reminder that if the US were unable to provide its allies with the systems and the expertise to fight in the 21st century, the EU would be forced to.
So it is no surprise that the EU defence plan goes further and has some controversial new ideas as well.
They include an effort to link intelligence networks, ready an EU cyber security network and facilitate intra-European military operations.
What might really scare us most is how EU commissioners plan to accelerate its defence capacity by spending around €3bn of other member states’ money – or their proceeds of justice fines – on the project over four years.
The British taxpayer won’t feel involved in any of this.
It’s another example of the EU’s promise of greater integration being delivered through a blunt barter deal.