Back-to-back world leader summits in Europe begin this weekend, with the goal of rallying Western nations behind Ukraine in its fight against Russia’s invasion and overcoming Turkey’s opposition to Finland and Sweden joining NATO.

The Group of Seven leading economic powers — the United States, Britain, Canada, France, Germany, Italy, and Japan — will meet in the Bavarian Alps in Germany, which holds the G-7’s rotating presidency this year.

Following the conclusion of the G-7, leaders from the NATO alliance’s 30 member countries will meet in Madrid for their annual summit on Wednesday and Thursday. Russia’s war in Ukraine will dominate both summits as leaders seek to project a united front against Kremlin aggression that has devastated Ukraine and plunged Europe and much of the rest of the world into economic and other crises.

Nations represented at the back-to-back meetings have sent billions of dollars in aid and arms to Ukraine and have united in their harsh condemnation of Russian President Vladimir Putin’s invasion.

Ukraine received another boost Thursday when European Union leaders unanimously approved its application to become a candidate for membership in the 27-nation bloc, though the process of joining will likely take years.

The United States and the European Union have imposed harsh economic sanctions on Moscow and Putin’s oligarchs, but major markets such as China and India continue to purchase Russian oil, reducing the impact of Western sanctions.

The membership of Finland and Sweden is a major unresolved issue for the NATO summit.

Russia’s war in Ukraine frightened both Nordic countries to the point where they abandoned their long-held neutrality policies and applied to join the military alliance. The applications must be approved by all 30 member countries. NATO Secretary-General Jens Stoltenberg supports the bid, and Biden showed his support by hosting the leaders of both countries in the Oval Office.

However, Turkish President Recep Tayyip Erdogan has so far slowed their admission, objecting to membership and pressuring both countries to change their stance on Kurdish insurgents whom Turkey considers terrorists.

All parties have been attempting to break the impasse, but whether Erdogan’s concerns can be addressed satisfactorily in Madrid remains to be seen. Sweden and Finland have been invited and are expected to participate.

NATO, which was established to contain the Soviet Union, is about to declare for the first time that confronting China’s rise is also part of its mission.

The alliance will unveil a new “Strategic Concept” in Madrid, the first update to its guiding principles since 2010, which explicitly mentions dealing with China’s challenges. The summit has also been invited by Pacific leaders from Japan, South Korea, New Zealand, and Australia.

The document represents a significant milestone in the United States’ efforts, under multiple presidents, to broaden the alliance’s focus to China, despite an increasingly bellicose Russia.

According to the Biden administration, Russia’s invasion of Ukraine has “firmed up” democracies against threats from autocracies in both Moscow and Beijing.

NATO, according to Chinese Foreign Ministry spokesman Wang Wenbin, is attempting to “start a new Cold War” and has warned against the alliance “drawing ideological lines that may induce confrontation.”

G-7 leaders will consider supporting a package of new climate change measures agreed to by senior officials last month.

These effectively require countries to phase out coal-fired electricity generation by 2035, to report transparently on their fossil-fuel subsidies, and to ensure that electric vehicles dominate new car sales by the end of the decade.

For the first time, senior G-7 officials acknowledged the need to provide developing countries with additional financial aid to deal with the loss and damage already occurring as a result of global warming. Wealthy nations have long opposed such a move, fearing they would be obligated to pay large compensation payments for decades of greenhouse gas emissions.

Poor countries want the G-7 to commit actual money after previous pledges of $100 billion in climate aid by 2020 fell through.

German Chancellor Olaf Scholz hopes they will also back his idea for an international “climate club” whose members would agree on minimum standards to avoid a patchwork of rules and emissions-related tariffs.