In the weeks since Russia invaded Ukraine on February 24, 2022, NATO and its European allies have moved to aid Ukraine through weapons, sanctions, and humanitarian relief. As Ukrainian president Volodymyr Zelensky continues to request weapons, aid, and the enforcement of a no-fly zone over his nation from the US and its allies, Russian president Vladmir Putin has continued to escalate his threatening rhetoric toward nations that assist Ukraine with security measures or weapons.

We asked a trio of SIS scholars with expertise in US foreign policy, NATO, proxy wars, and Russian politics to weigh in on the recent developments.

Is the war in Ukraine a proxy war? Why or why not?

Yes, although depending on which side's perspective you're adopting, the answer moves between "definitely yes" and "arguably yes." The view from Kyiv seems to be that the major separatist factions in the East are nothing more than cover for the Russian "special operation": proxies without any real legitimacy that exist only because Russia needs them as evidence that it is defending ethnic Russians from genocide by crossing the border. On the other side of the war, Moscow is certainly claiming that Ukraine is just a NATO proxy, but it's hard to make that point stick when foreign aid to the Ukrainians significantly predated the Russian attack, and Ukraine is an internationally recognized state rather than a breakaway province. --Professor Dylan Craig

Where is the line between assisting a nation that’s been invaded and sponsoring a proxy war? Is there a line, or does it depend on the assisting or sponsoring nation’s point of view?

As a strategy, proxy war only exists because sometimes obscuring what something is (War? Not-war?) has specific benefits to one or more of the participants—so one can spend a long time looking for an unobscured line and finding only frustration. We can legalistically assert that it's military aid when it goes to a recognized state but proxy war when it goes to a nonstate or insurgent group, but that's just making categories for things rather than describing their essence. In my work, the one thing that seems to approach the status of a line is: how much do the aims of the group you are sponsoring really matter to you? Will you give up some of what you want to ensure that they get what they want? If the answer is “no,” it's a proxy war. --Dylan Craig

What are the immediate challenges or dangers for European countries who are supporting Ukraine with weapons and other assistance?

One of the most important features of the war to date is that the US and NATO have been very careful not to get into a direct war with Russia by not sending troops to Ukraine or establishing a no-fly zone. And Putin has been very careful not to get into a direct war with the US and NATO. The West is supplying weapons to Ukraine; one possible danger is that Vladimir Putin would try to stop the flow of weapons into Ukraine, which could mean attacking NATO territory. So far, he has not done that, and that suggests he is deterred from doing so by the prospects of a larger war. Many European countries are dependent on Russia for energy, and we saw with Russia’s recent announcement that it will cut off Poland and Bulgaria from Russian energy supplies that the Kremlin may be tempted to use this dependence as a weapon against European countries. But that will only hasten the resolve of those countries to wean themselves off of that dependence. --Professor and former dean James Goldgeier

In late April, Russian foreign minister Sergei Lavrov dramatically warned, in response to NATO’s support for Ukraine, that the threat of a nuclear war “should not be underestimated.” While such a course of action remains highly unlikely and is more of an example of brinkmanship, European countries are still facing pressing threats in the field of energy. Within days of Lavrov’s statement, Russian company Gazprom chose to cut off gas supplies to Bulgaria and Poland, two countries that are very dependent on supplies from Russia. Other European countries are concerned that they could soon face the same predicament, which could lead to a steep rise in the price of gas and more pressure on consumers already dealing with inflation. --Professor Garret Martin

Do you believe Sweden and Finland will join NATO, and if so, how much of a sea of change does this represent among European nations who have tried to remain neutral during and since the Cold War?

It is now extremely likely that Sweden and Finland will join NATO. Becoming a member of the Alliance is still a process, but this will be a case of walking through an open door: the governments in Helsinki and Stockholm intend to jointly announce their candidacy in a matter of weeks; public opinion in Finland and Sweden are now strongly in support of doing so; and NATO would welcome both states with open arms, in part because of Finland and Sweden’s military assets and the history of deep cooperation with the Alliance. This likely dramatic switch for the Nordic states is further evidence that the war in Ukraine is causing a fundamental realignment of the European security order, be it Germany doubling defense spending or neutral nations reconsidering their traditional stances, such as Ireland and Switzerland.--Garret Martin

Sweden and Finland are likely to ask to join NATO, and NATO is likely to accept them. All 30 current members have to ratify this, so that will take time to go through the parliaments. The Biden administration has announced its support. It shows that Putin’s aggression has created popular support for NATO membership where little existed before, as occurred in Ukraine in 2014 and now in Sweden and Finland. These two countries joining NATO gives the alliance a much stronger presence in Northeastern Europe, and it is truly remarkable that it is likely to occur. --James Goldgeier

US Defense Secretary Lloyd Austin said earlier this week that the US would like to see “Russia weakened to the degree that it can't do the kinds of things that it has done in invading Ukraine." Were you surprised that he said this, and why or why not?

I wasn’t surprised that this would be the policy. After all, national security adviser Jake Sullivan said on April 10 on Meet the Press that the United States wanted to see a “weakened and isolated Russia.” But having US officials say the quiet part out loud has raised concerns in some parts of the globe that this isn’t just about helping Ukraine defend itself but about creating US advantages over Russia, and that may be a problem for maintaining support outside of the American alliance system, especially in the Global South where there are often concerns about US foreign policy motives. --James Goldgeier

Russian Foreign Minister Sergei Lavrov on April 25 said that the threat of a nuclear conflict “should not be underestimated.” What does this mean? Has a critical line been crossed when officials begin to publicly refer to nuclear conflict?

The Russians have made many implicit nuclear threats during this war, and it’s a terrible precedent they are setting. I do believe it is just bluster given that it would cross a line in world politics that should absolutely not be crossed. Nikita Khrushchev made these kinds of threats early in his time in power, and it didn’t really help him much. I don’t think it’s likely to redound to Putin’s advantage, either. --James Goldgeier