The EU's goal is to have sufficient military strength by 2030 to deter Russia from starting new wars.
Prime Minister Ulf Kristersson (The Moderate Party) pointed out in the EU Committee before the summit that Russia is expected to have the ability to attack countries other than Ukraine within five years.
It's therefore urgent to do everything required to be able to meet a Russia once again, he said.
NATO leads Europe's defense and military buildup is the responsibility of the member states, but the EU supports through cheap loans, by allowing larger national budget deficits and by facilitating defense industrial cooperation.
In Copenhagen, no decisions will be made, but they will discuss which buildup projects should be prioritized and how the defense preparations of the member countries along the eastern flank can be supported more.
A drone barrier
After Russian drones flew into Poland a few weeks ago, the discussion about a drone barrier has gained new momentum. The idea is now supported by the EU Commission, which is working on a proposal.
The issue of drone defense has become even hotter after Denmark, ahead of the summit, has been forced to close airports on several occasions due to unknown drones in the airspace.
Denmark's Prime Minister calls the intrusions hybrid warfare. Sweden, Germany, and France have now lent out anti-drone systems so that the summit will not be disrupted.
However, Germany's Defense Minister Boris Pistorius wants to dampen expectations of a drone barrier.
We're not talking about a concept that can be realized within the next three to four years, he said earlier in the week, according to Politico.
Hungary is blocking
The EU leaders will also discuss long-term support for Ukraine. The EU Commission has proposed that Ukraine should be able to take interest-free loans from the Russian assets that are frozen in the EU. However, there are several objections to such plans.
So far, only the returns from the Russian assets have gone to Ukraine. Sweden and Finland are driving for the assets themselves to be used and now seem to have gotten Germany on their side.
That Germany is reconsidering its position gives further momentum, says Kristersson.
The summit will also discuss how to get Ukraine's EU membership negotiations moving. They are being blocked by Hungary.
Increase the pressure on Hungary so that Ukraine can move forward in the negotiations, says Kristersson.
An idea to be tested at the summit is that decisions to open different negotiation chapters are made with a qualified majority instead of unanimously. But such a change requires all countries to say yes.
