During the NATO summit on 3-4 December 2019, NATO leaders reaffirmed the collective defence commitments of the 29 members of the Alliance. This is stated in the joint declaration released on December 4, after the summit in London dedicated to the 70th anniversary of the defense Union. "We confirm the permanent transatlantic link between Europe and North America... and our official obligation under article 5 of the Washington Treaty that an attack against one ally will be considered as an attack against all of us," the statement said. The document also points to the need to overcome the challenges posed by "China's growing influence". The statement also said that Russia's aggressive actions are a threat to Euro-Atlantic security.

After a debate caused by comments of the French President, Emmanuel Macron about "brain death" of NATO, Alliance leaders agreed on a "perspective  thinking process ... to further strengthen the political aspect of NATO."  On Tuesday 3 December, NATO leaders met in various groups in London before a joint dinner with Britain's Queen, Elizabeth II at Buckingham Palace. At the same time Macron refused to disavow his statements about "brain death" of NATO and Trump continued to insist that some capitals are delaying proper payments.

On Wednesday, December 4th, the summit gathered for a three-hour working session, after which a joint statement was presented, and the host of the summit, British Prime Minister, Boris Johnson, appealed for unity. "After 70 years, we are firm in our commitment to NATO and the giant shield of solidarity that today protects 29 countries and about a billion people" Johnson said. "If NATO had a motto, it would be: one for all, all for one". Later, in a joint appearance with Macron, Trump softened his tone, but the French leader insisted on his approach and his formulations and accused Turkey of contacts with extremists.

What kind of relations should Alliance have with Russia? To this question, President Trump replied: "President Macron and I have quite similar positions on this issue. I think we feel we can get along with Russia. I think it's a good thing to get along with Russia". Macron said that while "it is important to have a strategic dialogue with Russia" it should be done "without naivety". Macron and Turkish President, Recep Tayyip Erdo?an later met face-to-face in four-way talks with German Chancellor, Angela Merkel and British Prime Minister, Boris Johnson. Erdo?an has threatened to block NATO's efforts to strengthen the Baltic states' defense against Russia unless Alliance members declare Kurdish militias as a terrorists  who have fought "Islamic State in Syria".

The specific content of the summit quite modest: there was only one three-hour joint meeting of the leaders, at which a number of decisions already agreed by the Ministers of Foreign Affairs and Defense were signed. In particular, it was about the declaration of space as another sphere of military operations, along with land, sea, air and cyberspace. They also recognize for the first time the "challenges" associated with the rise of China.  It should be noted that there is not a single word about Ukraine in the relatively large joint declaration of NATO. This is despite the fact that on the eve of the summit, Jens Stoltenberg said that the Alliance will discuss the war in the Donbas and preparations for the Normandy meeting. Herewith NATO noted that despite the recognition of the existing threat from Russia, NATO needs to strengthen relations with it. So to say, Russia is the largest and closest neighbor. And they will continue to "take a measured and responsible approach" to Russia's deployment of new medium-range missiles and will intensify actions to protect freedoms at sea and in the air.[1]

The Minister of Foreign Affairs of Ukraine, Vadym Prystaiko at the NATO Engages conference in London stated that NATO's indecision allowed Russia to invade Ukraine and Georgia. "What happened 10 years ago in Bucharest, on my opinion, was a big mistake. At first, we were promised membership, then there was an idea for a Membership Action Plan. It has been more than 10 years, and we were not invited nor road maps, nor to the membership" Prystaiko said. "I believe that NATO's indecision allowed Russia to invade Georgia and then six years later to come to Ukraine"  the Minister added.  Commenting on the discussion that is taking place in NATO at the initiative of the President of France on the definition of the Alliance of its main enemy – Russia or terrorism – Prystaiko said that the fight against Russia is part of the fight against terrorism. "I don't see the difference between terrorism and Russia. Terrorism is an action to achieve a political goal through intimidation. Is anyone going to say that Russia is doing something different?" he explained.

The Minister of Foreign Affairs of Ukraine said that Russia's actions in the occupied part of Ukraine, with attempts to influence the Ukrainian government, is an example of such influence. Also in London, the Minister added: the President of Ukraine, Volodymyr Zelensky did not come to London, because the format of the meeting of leaders does not provide for the invitation of partner states. "We are not invited because we are not yet members of NATO. I want to remind you that we have been trying to become a part of NATO for many years, and despite the fact that we are at war, we maintain this course. I want to remind the leaders of this" the Minister said.[2] 

Expert on the North Atlantic Alliance, Rachel Ellehuus about the London conference said: "The final statement confirms an open door policy, which means that both Ukraine and Georgia are on the way to membership, and that the relationship will continue, and someday they will become members of the Alliance. I think we should invest in that, make sure we do everything we can to keep Ukraine and Georgia safe – as safe as possible – even if they are not yet NATO members". The expert expressed the opinion that now there are "political disagreements" in the Alliance: "I think that this is the imprint of disunity at the level of states. A lot of NATO governments are in a split situation where the center is no longer holding the situation and they have to take into account the opinions and views of parties from both the right and the left of the political spectrum. And this disunity affects NATO as well. I also believe that the nature of the challenges and the scale of the challenges now facing the Alliance are very complex. Because there are a lot of them, because it is very difficult to prioritize."[3]

Given the above, disputes between the states that dominated during the NATO summit threaten to undermine unity within NATO itself. The main drawbacks are that not enough attention was paid to the countries-applicants for membership in NATO and the real counteraction to Russian aggression, and moreover, during the meeting there were signals of sympathy for Russia. Nevertheless, following the summit, collective security remains a top priority for NATO leaders.