NATO's new chief is inheriting messy wars and a possible second Trump presidency. It's not going to be easy, security analysts say.

NATO has a new leader at its helm.

Mark Rutte, the Netherlands' longest-serving prime minister, replaced Jens Stoltenberg as NATO's new secretary-general on October 1, at what is seen as a crucial and turbulent time for the alliance, with ongoing conflicts in Ukraine and Gaza, and the US election in November.

He is entering his term "with threats and challenges everywhere," Abishur Prakash, the founder of The Geopolitical Business, Inc., a strategy advisory firm in Toronto, told BI.

Rutte will not only have to decide the next phase of NATO's involvement in the Ukraine war, but will also have to navigate whether NATO chooses to come to Israel's aid and how to deal with the possibility of reduced US commitment to the alliance, Prakash added.

"Stoltenberg left big shoes to fill," said John Hardie, deputy director of the Russia Program at the Foundation for Defense of Democracies.

"Rutte will need to take the baton in terms of pushing alliance members to fulfill their defense spending commitments and continue providing aid to Ukraine," he said.

And then, with the US presidential elections now less than five weeks away, there is the prospect of a second Donald Trump presidency.

Rutte has experience working with Trump: He earned the nickname the "Trump whisperer" for his ability to appease the former president when he threatened to go his "own way" during a NATO meeting in 2018, per Politico .

Even so, a Trump victory in November would "present a challenge for Rutte in terms of managing that relationship and maintaining alliance unity," Hardie said.

Russia-Ukraine war

Rutte's most pressing NATO challenge stepping into his new role is figuring out the alliance's stance on letting Ukraine use Western long-range weapons to hit targets deep inside Russia, Prakash said.

Ukrainian President Volodymyr Zelenskyy views permission to use Western weapons to strike Russia as a key part of the "victory plan" he presented to US officials last week.

However, the alliance has shown differences of opinion on the matter, with countries like Denmark , Sweden, the Czech Republic, and Finland publicly saying that Ukraine can use their weapons but others showing more reluctance.

The Pentagon justified the US decision not to allow such strikes last month, saying that 90% of Russian aircraft launching glide bombs are out of range of Ukraine's ATACMS, and also cited the potential for an escalation in the conflict .

Pressure, however, is building. In late August, Josep Borrell, the EU's foreign policy chief, said EU countries should lift restrictions on the use of weaponry against Russian military targets "in accordance with international law."

Several top House Republicans also signed a letter on September 9 urging President Joe Biden to lift the remaining restrictions on US-provided long-range systems, including the ATACMS, against "legitimate" military targets deeper inside Russia.

And in a resolution adopted on September 19, the European Parliament called on EU countries to lift restrictions preventing Ukraine from using Western weapons systems against "legitimate" military targets inside Russia.

Escalating tensions in the Middle East

Prakash said NATO would also have to decide whether to get involved in the Middle East.

Since Hamas' October 7 terror attacks on Israel and Israel's subsequent invasion of Gaza, tensions have ramped up between Israel and Hamas, Hezbollah, and the Houthis.

Violence between Israel and the Lebanon-based Hezbollah militia intensified last month, and Lebanon recorded its deadliest day for decades after Israel ramped up strikes on the country.

This followed the deadly pager and walkie-talkie explosions that hit Hezbollah members in Lebanon.

Hezbollah has blamed Israel for those attacks, but it has not yet claimed responsibility.

The US has stepped up diplomatic and military efforts in the region to try to bring about a cease-fire — but NATO has so far not gotten involved.

Benjamin Friedman, policy director at the Defense Priorities think tank, said the alliance will likely not play any role as it has enough on its hands with Ukraine.

"They have enough to do in Europe, and I think NATO should focus on Europe," he told BI.

US elections

However, the US presidential election could be a decisive factor in NATO's trajectory in the coming years.

Keir Giles, a senior consulting fellow at Chatham House's Russia and Eurasia Programme, said that "it's not going to get easier" if Trump is elected in November.

During his time in office, the former president publicly threatened to leave NATO if other members failed to meet their commitments to spend 2% of their GDP on defense.

Congress passed a bill in 2023 to prevent a president from suspending, terminating, denouncing, or withdrawing the US from NATO, except via an Act of Congress or the approval of two-thirds of senators in attendance.

But if elected, Trump could still heavily influence NATO, including by reducing the US military presence in Ukraine, withholding support for NATO's Article 5 mutual defense pact, or limiting America's involvement in the alliance.

In a rally speech last month, he again argued for ending US involvement in the war in Ukraine.

Even if Trump loses, he could still exert "baleful" influence on US politics and get in the way of policy initiatives through his network of supporters, Giles said, pointing to Republicans blocking aid to Ukraine earlier this year.

Friedman of Defense Priorities struck a more positive tone, saying he doesn't believe Trump is "seriously" considering withdrawing US commitment to the alliance.

The "big question," Friedman says, is whether Trump, if elected, would behave like he did during his first term, which he said was "more bark than bite."

Meanwhile, Prakash said that ongoing geopolitical flashpoints and tensions around the world could actually result in Trump and Vice President Kamala Harris being markedly similar US presidents on the world stage.

Prakash cited the ongoing territorial disputes in the South China Sea between the Philippines, a US ally, and China as likely the "single greatest" flash point facing the US right now.

If Harris "feels that NATO doesn't connect with that in its current form, then she may also raise objections to NATO," he said. "So, it is not just Trump."

Looking beyond Europe

NATO appears to be considering the possibility of a reduced US commitment to the alliance.

In April, Stoltenberg, the outgoing secretary-general, proposed shifting control of the Ukraine Defense Contact Group, which organizes the delivery of weapons to Ukraine, from the US to the alliance.

NATO also established the NATO Security Assistance and Training for Ukraine, or NSATU , in July, to coordinate the future supply of military aid and training for Kyiv, amid growing concern about a potential change in US leadership.

However, Rutte's past statements and familiarity with Trump suggest he would try to keep the US in the fold.

And in an op-ed for Dutch newspaper NRC in 2023, a year after Russia launched its full-scale invasion of Ukraine, Rutte stressed how different the first year of the war would have been without the "colossal" deployment of US material and resources.

According to Prakash, Rutte is "coming into the role from a certain outlook, and that outlook is essentially saying: 'We need to stand with America.'"

Beyond the most immediate threat of Russia in Europe, NATO may also want to tackle the China threat, he said.

NATO's deputy secretary-general, Mircea Geoană, told Euronews in July that China, as a direct enabler of Russia's war in Ukraine, threatened the alliance's security.

Shifting NATO away from Russia and toward other threats is going to be "perhaps the greatest challenge facing Mark Rutte," Prakash said.

All in all, it's likely to be a bumpy ride for NATO's new chief.