Brussels is bracing itself for the arrival of several heads of state and government, including Donald Trump, for the NATO summit. On the agenda this year will be presentations by NATO leaders as well as the unveiling of the new NATO headquarters, which has a sanctioned budget of €1.12 billion.

The summit will revolve around two main topics, NATO Secretary General Jens Stoltenberg told reporters on Wednesday. The first will be a discussion on how NATO can combat terrorism and the second, “burden sharing”, or the distribution of financial and operational responsibilities across the 28-member alliance.

A theme that runs through the summit is the showcasing of NATO to Mr. Trump, who had called the alliance “obsolete” during his presidential campaign, although he reversed his position during Mr. Stoltenberg’s visit to the White House earlier this year. “Tomorrow’s meeting will demonstrate NATO’s ability to change as the world changes,” Mr. Stoltenberg said.

While his stated position on the alliance’s efficacy may have changed, Mr. Trump has continued to maintain, as the U.S. establishment has in the past, that not all NATO members are pulling their weight. Mr. Trump had also said that Germany, which, in recent years, has spent 1.19% of its GDP on defence , owes NATO and the U.S. money.

NATO uses two metrics as guidelines for member contributions – a defence budget of at least 2% of GDP and a target of 20% of defence expenditure on major equipment and related R&D. Countries have committed to achieving the 2% target by 2024, but only a handful — Poland, the U.K., Estonia, Greece and the U.S. — currently meet it.

However, the U.S.’s understanding of responsibility towards the alliance is not the same as that of other members. “Burden sharing is not just about spending, it is also about capabilities and contributions to NATO missions, operations and other engagements,” Mr. Stoltenberg said. In addition to discussing the contours of responsibility, NATO will also welcome a new member this year — Montenegro.

EU meetings

Mr. Trump is also scheduled to meet Donald Tusk, President of the European Council, and other leaders of the EU on Thursday morning. The EU has had strained relationship with Mr. Trump who supported Brexit and at one point expressed doubts about the EU and said countries would follow Britain in leaving the union.

Turkey’s President, Recep Tayyip Erdogan, who, like Mr. Trump, has been at the centre of several controversies, is also expected to be in Brussels on Thursday, for meetings with NATO as well as with Mr. Tusk.

Mr. Erdogan and Mr. Tusk are expected to discuss the modernisation of the customs union, visa-free travel for Turkish citizens — the outcome of a deal struck with the EU in return for Turkey holding refugees from West Asia within its borders, and issues around the Cyprus reunification talks, Demir Murat Seyrek, of the European Foundation of Democracy, told The Hindu. Turkey’s accession to the EU has stalled since Mr. Erdogan clamped down on individuals and institutions suspected of participating in a failed coup against him last year.