Biden Is Hosting NATO This Week. Here’s What to Watch.

As NATO leaders gather in Washington starting Tuesday, they will celebrate the strength of their alliance on its 75th anniversary while confronting deep uncertainty about its future.

In recent years, Russia’s aggression against Ukraine has given NATO, founded after World War II to defend Europe from the Soviet Union, a renewed sense of purpose. But the alliance also faces grave threats, including from right-wing skeptics who are gaining power in nations such as Germany and France.

And the potential return to the White House of Donald J. Trump, who has derided NATO and even mused about withdrawing the United States from the alliance, has raised alarms among its members.

Here’s what to watch for during the three days of NATO meetings in Washington this week.

Staring Down Putin

Perhaps the summit’s most important goal will be sending a signal of unity and strength to Moscow.

Officials say that President Vladimir V. Putin of Russia is counting on NATO’s efforts to counter his aggression to dwindle, potentially allowing him to conquer much more of Ukraine and even turn his sights to other nations.

That’s why a central theme of the summit will be demonstrating not only a long-term commitment to Ukraine, but also the endurance of NATO itself.

Secretary of State Antony J. Blinken said last week that the summit’s “main purpose” would be to showcase the value of spending on Europe’s collective defense. He noted that security agreements struck recently between dozens of NATO members and Ukraine would help to “tell Vladimir Putin that he can’t out-wait Ukraine, he can’t out-wait all of Ukraine’s partners.”

The NATO leaders nevertheless remain cautious on the subject of granting Ukraine membership into the alliance, something first promised to Kyiv in 2008. Most member states say that is impossible while Ukraine and Russia are at war.

One wild card this week is the possibility that Mr. Putin might pull a stunt to disrupt the party.

“Senior Biden administration officials are concerned that Russian President Vladimir Putin has more surprises in store for them regarding Ukraine, timed to disrupt and upstage NATO’s 75th-anniversary summit in Washington,” Frederick Kempe, the president of the Atlantic Council, wrote last month.

Russian sabotage

This year, U.S. and allied officials have said, Russian military intelligence began a covert sabotage campaign across Europe, setting fires at warehouses and other sites associated with the effort to supply Ukraine.

Most of the attacks had the potential to delay the flow of supplies to Ukraine, but some were just odd: One target was an Ikea in Lithuania.

NATO is taking the attacks seriously, issuing warnings and bringing in senior American intelligence officials to brief ambassadors.

As Ukraine has used a flow of new weaponry to strike into Russia and at Russian military targets in occupied Crimea, the Kremlin has increased its threats. After a strike on Crimea using an American-provided ATACMS missile, the Kremlin warned that the death of Russians “must have consequences.”

In response, the U.S. military raised its alert level on bases across Europe.

A big question for NATO leaders is whether Mr. Putin is ready to escalate the war beyond Ukraine’s borders. Western intelligence agencies don’t think he is. But the alliance is likely to warn Mr. Putin that it will respond if he continues or escalates covert attacks on Europe.

Ukraine’s weapons wish list

At the top of Ukraine’s weapons wish list are two familiar asks: more air defenses and more air defense missiles.

The Biden administration announced a $2.3 billion military aid package for Ukraine last week. About $150 million of those munitions, including air defense interceptors, artillery and mortar rounds, and anti-tank weapons, will be drawn from Pentagon stocks and sent immediately to Ukraine.

Of the remainder, the Pentagon will purchase $2.2 billion worth of Patriot and other air defense missiles from defense contractors to be delivered to Ukraine in the coming months. The Biden administration said last month that it plans to accelerate delivery of these Patriot interceptors to Ukraine by delaying certain weapons shipments to other countries.

President Volodymyr Zelensky of Ukraine has said he desperately needs at least seven Patriot batteries. President Biden has promised that five Western air defense systems would soon be delivered to Ukraine.

Beyond manpower, Ukraine’s biggest battlefield need remains air defenses, both at the front and to defend critical infrastructure, including the nation’s electricity grid.

Michael Kofman, a senior fellow in the Russia and Eurasia program at the Carnegie Endowment for International Peace, who recently visited the battlefront, said that Ukrainian air defenses are struggling to deal with a flood of Russian drones flying behind Ukraine’s front lines.

Ukraine is also dealing with large volumes of Russian glide-bomb strikes, which are increasingly more accurate, he said.

“The growing number of Russian drones able to fly well behind Ukraine’s front lines is one of the most significant problems,” Mr. Koffman said. “However, the most pressing is a deficit of air defense systems to defend infrastructure, and the need to address shortfalls in Ukraine’s electricity grid ahead of the winter.”

Patriots and HAWKs

Ukraine’s urgent need for air defense weapons was underscored on Monday by a wave of Russian missile strikes across the country, including one damaging a children’s hospital in Kyiv.

One topic of conversation at the summit will revolve around how many nations can send air defense weapons to protect the skies over Ukraine.

The United States is sending more missiles for its most modern system, the Patriot. It will also supply an American system long retired from Pentagon service called HAWK, for Homing All the Way Killer, that is still in service with several allied nations.

“The HAWK system was developed by Raytheon in the 1950s and was first fielded by the Army in 1959,” Marc Romanych, a retired U.S. Army air defense officer, said in an interview. “The United States never fired a HAWK missile at a hostile target, but other militaries did and were quite successful.”

Mr. Romanych commanded a HAWK unit while on active duty and wrote a book about the weapon in 2022.

The HAWK, he said, was built for shooting down low-altitude Soviet warplanes traveling at twice the speed of sound and would be able to take down much slower-moving drones that Russia is using in Ukraine.

According to the Missile Defense Project at Washington’s Center for Strategic and International Studies, the missiles have a range of about 28 miles.

In October 2022, Spain announced that it would provide four HAWK launchers to Ukraine. Less than a month later, the Pentagon said it was providing the missiles for those launchers and would begin refurbishing more missiles from its stockpiles to ship later.

The Pentagon said it would send two more HAWK launchers to Ukraine in February 2023, along with more launchers and missiles for them in June that year. In just the past month, the Pentagon announced two more shipments of HAWK missiles.

At the same time, the U.S. military announced a major new purchase of the most advanced Patriot missiles, many of which have been sent to Ukraine.

Which Zelensky?

Last year, President Volodymyr Zelensky of Ukraine fired off angry social media posts before he flew to the NATO summit in Vilnius, Lithuania, upset that allies were discussing an invitation to Ukraine, rather than a timetable for membership.

The post said the lack of a timetable would encourage Russia “to continue its terror.” At the time, White House officials groused that Mr. Zelensky appeared ungrateful, a bad look given the billions of dollars the West had spent to help him defend the country.

Diplomats now acknowledge that NATO offered Mr. Zelensky a “word salad,” rather than a strengthened statement about membership in the alliance. So this time, the United States and other nations are pushing for a clear statement on Ukraine’s future membership.

There has also been an intense diplomatic push to set Mr. Zelensky’s expectations ahead of the summit. In visits to Kyiv, NATO allies have reinforced their commitment to providing more weaponry, improving training and offering security guarantees to Ukraine. The message is that while alliance membership will someday and in the meantime no priority is higher for NATO than supporting Kyiv.

Will that diplomatic whirlwind succeed in bringing out the grateful version of Mr. Zelensky? Diplomats concede they cannot know. Mr. Zelensky is one of the world’s great communicators and only he will determine what message he delivers to allies in Washington this week.

The 2024 U.S. election

Looming over the summit is the uncertainty about whether Mr. Biden will remain the Democratic presidential nominee — and the possibility of the return of Donald J. Trump to the White House.

Mr. Trump has declared NATO “obsolete” and threatened to leave the alliance, although some European officials privately say they believe he would not follow through on those threats if elected. He has long complained that NATO members do not spend enough on their collective defense, which is one reason the alliance is trumpeting increased member spending in recent years.

Mr. Trump has also promised that if elected, he would negotiate a quick peace between Russia and Ukraine, though he has offered few details of his plan. Such negotiations would probably force Ukraine to give up territory and its ambitions to join NATO.

But the spotlight at the summit will fall on Mr. Biden, who will face close scrutiny for any new signs that his health or mental acuity may be faltering. Should Mr. Biden not remain on the Democratic ticket, it is unlikely that a different Democratic nominee would call for major changes to NATO or U.S. support for Ukraine.