Who will be NATO's next chief? The race is on.

The Russian war against Ukraine has given NATO a renewed sense of its vital role in the defence of Europe. With the risks of escalation and wider war, this period may be as important as any in the history of the 73-year-old alliance, which was designed to deter the Soviet Union.

With the tenure of NATO’s current chief, Jens Stoltenberg, scheduled to end next fall, the jockeying among allies for who should replace him has begun in earnest, and the battle lines in the contest are already beginning to form, according to American officials familiar with the debate, New York Times reports.

While the officials cautioned that these are early days, and very often the names that surface first do not survive the bargaining among NATO’s 30 members, they said one prime candidate has surfaced in Washington: Chrystia Freeland, 54, the Canadian-Ukrainian deputy prime minister and finance minister of Canada.

Ms. Freeland, 54, a former journalist (who is married to a reporter for The New York Times), has also been Canada’s foreign minister. Her advantages are considerable: she speaks English, French, Italian, Ukrainian and Russian; she has run complicated ministries; she is good at news conferences and other public appearances; and she would be the first woman and first Canadian ever to run NATO.

The United States does not put forward an American candidate, since an American general is traditionally the Supreme Allied Commander Europe, but it understandably has a strong voice in the choice.

The United States does not put forward an American candidate, but in Washington, Chrystia Freeland, the deputy prime minister and finance minister of Canada, is considered a strong choice.

The European Union, not surprisingly, would like the next NATO head to be from a member country — 21 of its current 27 states belong to the alliance. And presuming Sweden and Finland are approved for NATO membership, the European Union would have 23 of 32 members.

Although the Europeans have yet to coalesce around a single candidate, they, too, have several strong contenders who are women, including Kaja Kallas, 45, the prime minister of Estonia; Zuzana Caputova, 49, the president of Slovakia; and Kolinda Grabar-Kitarovic, 54, who was president of Croatia from 2015-20, was Croatia’s ambassador to Washington and has worked at NATO as assistant secretary general for public diplomacy.

Britain, which has left the European Union but not NATO, has a contender in Ben Wallace, 52, its defence secretary. Some officials suggested he has stayed in that job despite Britain’s governmental merry-go-round not only to provide stability in support for Ukraine, but also to increase his chances for the NATO post, which London dearly wants as another symbol of its post-Brexit engagement in the world.

The person who gets the job will undoubtedly take over at one of the most critical junctures in the history of the alliance. The war in Ukraine has meant more NATO troops on Russia’s borders, potential new members in Sweden and Finland, and new demands for money and equipment. While NATO works by consensus, its head plays an important role in conciliating the demands of its member states and in articulating the position of the West to a global audience.

There are issues with all of the possible candidates, and it is also possible, a NATO official suggested, that member states could agree to extend Mr. Stoltenberg’s term by another year. (Mr. Stoltenberg, 63, had asked for a two-year extension because of the war, and was given one year, or until next September.)

The choice could also be made more complicated by elections in spring 2024 that will select new leadership for the European Union. That kicks off a deeply competitive process among member states as they divvy up jobs. In general, a NATO official said, Washington wants to avoid the possibility that the next NATO leader is seen as getting a consolation prize for not securing a major E.U. post, so it would prefer that the choice is made before that election. Both Washington and Brussels want a conclusion before the next American presidential election in November 2024.

Where any of the candidates come down on support for Ukraine in the war against Russia will be a critical factor. However strongly opposed they are to Russia’s invasion of Ukraine, countries of Western Europe, like France and Germany, want to look past the day the war ends, one way or another, and will want someone willing to try to create a new, more stable relationship with Moscow.

The Estonian, Ms. Kallas, has been strong in support of Ukraine and very vocal, raising her international profile, but it is possible that anyone from the Baltic nations or Poland, no matter their qualities, would be considered too fiercely anti-Russian for the rest of NATO. Ms. Kallas has opposed any negotiations with Vladimir V. Putin, the president of Russia, and has accused Russia of genocide in Ukraine.

Ms. Freeland, too, is a strong supporter of Ukraine and its fight against Russian aggression, but unlike Estonia, Slovakia or Croatia, Canada is a NATO laggard in how much it spends on defense, far from the 2 percent of gross domestic product that member states cited as their goal by 2024.

Still, Canada has provided sizable economic and military support to Ukraine, just after Germany and just ahead of Poland, though far behind that of the United States and Britain. And Ms. Freeland’s views on Ukraine may also be too strong for some. She went to Kyiv in 2014 to celebrate the overthrow of the Kremlin-supported Ukrainian president, Viktor Yanukovych, and meet officials there. To her regret, Russia then put her on what is now a lengthy list of banned individuals.

There is also an older concern, dismissed by Prime Minister Justin Trudeau, that her Ukrainian grandfather, a grateful immigrant to Canada, was as a younger man involved with a Ukrainian nationalist movement that saw the Nazis as useful foils to counter the Soviets.

To the end of their lives, Ms. Freeland wrote in 2015 in an essay called “My Ukraine,” her maternal grandparents “saw themselves as political exiles with a responsibility to keep alive the idea of an independent Ukraine, which had last existed, briefly, during and after the chaos of the 1917 Russian Revolution.” She continued: “That dream persisted into the next generation, and in some cases the generation after that.”

Ms. Freeland, through a spokesman, made clear that she is actively engaged in her current job and has not herself put her name forward. “Ms. Freeland already has an important job and is focused on serving Canada and Canadians,” said her spokesman, Alex Lawrence.