It is unclear how NATO would respond if Russia attempted a limited hybrid attack or incursion on the alliance's territory.

NATO condemned Russia's 2022 invasion of Ukraine

While Ukraine is not a member, NATO responded forcefully to the Russian invasion of the country in 2022. This page from the NATO website offers answers to frequently asked questions about NATO’s response to the invasion, specifically on how NATO is aiding Ukraine.

Tensions between the US and European NATO allies

The Associated Press article discusses US Defense Secretary Pete Hegseth's assertion in February of 2025 that restoring Ukraine's prewar borders or NATO membership for the country are both unrealistic. This represented a large rift between the United States and its other NATO allies, prompting concern about America’s commitment to the future of the alliance.

Members decide to what extent they respond to an attack on an ally

The NATO constitution is intentionally vague about what exactly is required from its members. Explore the historical debates and learn more about common misconceptions about NATO’s common defense clause.

NATO has only invoked its mutual defense clause once, in the days after the 9/11 attacks.

The alliance operates under a "flexible response" doctrine—that is, proportionality

NATO countries' main deterrent against aggression is their ability to respond with nuclear weapons. This video from "The Infographics Show" outlines the purpose of this nuclear arsenal, NATO’s strategy to prevent attacks, and its plans in the event of escalation toward nuclear war.

How NATO responded to 9/11

The collective defense clause of the NATO constitution has only been invoked one time: after the 9/11 terrorist attacks against the United States. This video explores the immediate actions NATO took to respond to the attacks to support the United States. These firsthand clips from 2001 give a sense of the magnitude of the moment and the difficult decisions facing NATO leaders at the time.

NATO leads cyber war games in Estonia

Estonia is host to one of the world’s largest annual interactive cybersecurity drills. Russia is always considered the main threat, but this year, the war in Ukraine has only added to the stakes.

Finland and Sweden joined NATO after Russia's invasion of Ukraine

In response to Russia's 2022 invasion of Ukraine, Finland and Sweden abandoned decades of military neutrality to join NATO, marking a major shift in Europe's security landscape and expanding the alliance to Russia's borders.

The treaty's Article 5 requires mutual defense, but not necessarily military action.

As of 2025, every NATO member spent at least 2% of GDP on defense, a target the alliance had been pushing toward for over a decade.

NATO's Article 5 has been invoked once—after 9/11

The article was invoked the day after the attacks and launched a series of NATO campaigns to fight global terrorism. This page includes excerpts from a speech by then-NATO Secretary General Jens Stoltenberg about the attacks and the organization’s response.

NATO consists of 32 countries across North America and Europe.

Germany is pursuing its most significant military buildup since WWII.

NATO was formed in 1949 to deter Soviet expansion, prevent European militarism, and encourage political integration.

Breaking down Europe's reliance on Russian energy (preinvasion)

One side effect of the Russian-Ukraine conflict is how it underscored European dependence on Russian natural gas and oil. This article, published days before the Russian attacks, outlines and illustrated how much gas and oil flows from Russia to Europe and the potential for either side to use sanctions to get what they want.

Russia's full-scale invasion of Ukraine began on Feb. 24, 2022

Russia launched a massive multifront assault from Belarus, Russia, and Crimea, aiming to seize Kyiv within days. Instead, Ukrainian forces repelled the advance, halting Moscow's plans for a rapid takeover.

Many countries remained neutral after Russia's invasion of Ukraine

Following Russia's 2022 invasion of Ukraine, few nations outside the West imposed sanctions on Moscow. Major powers such as China, India, Brazil, and Turkey remained neutral, underscoring global divisions over how to confront Russian aggression.

The origins of Putin's 'Nazism' claim in Ukraine

Ukraine has had a varied history, and is home to a rich diversity of ethnicities, religions, and people. In the time leading up to Russia's attacks on the country, Russian President Vladimir Putin referred to Ukraine as a "Nazi nation", owing to Ukrainian nationalists' acceptance of the invading Nazis as liberators from the Soviet Union in WWII. The history is more complex than that. Read this Smithsonian Magazine article to learn more.

Russia's invasion of Ukraine has destabilized safety and oversight at Chernobyl

Russian forces cut power and disabled monitoring of the decommissioned nuclear power plant in 2022, endangering operators at Chernobyl. In February 2025, a Russian drone struck the confinement structure—part of broader efforts to pressure Ukraine's energy infrastructure—punching a hole in the containment shell.

The day Russia invaded Ukraine—an oral history

Experience the slow build-up to the Russian-Ukraine war, to the moment when it was clear Putin intended to invade, to the actual invasion and occupation in this oral history compiled by Politico. Multiple US and Western officials share their perspectives and thoughts on the war, how it's been conducted, and what can happen next.

Putin claimed the invasion of Ukraine was to demilitarize and 'denazify' the country

In a 5,000-word historical treatise he wrote himself, President Vladimir Putin claimed the move was meant to restore Russia's historic lands. Many Western historians and global leaders described these narratives as false pretexts for aggression.

Breaking down Western military weapons in Ukraine

Since the beginning of the Russian invasion of Ukraine in February 2022, Western military aid has helped dictate Ukraine's capability and strategy on the battlefield. From advanced ground-launched missiles to millions of rounds of ammunition, the supplies have been critical for Ukraine but force Western countries to tip-toe around the appearance of direct conflict with Russia. This visual deep-dive breaks down some of the most important military aid to date.

Questions about the US' commitment to its allies may have sparked a new nuclear age

Some US allies—from Warsaw to Seoul—are reevaluating their security amid doubts over American nuclear commitment, signaling the possibility they may want to acquire their own weapons.

Anonymous' war against Russia

Anonymous has been waging a cyber war on Russia for invading Ukraine. CNBC takes a look at how effective the collective’s six main strategies have been.

Ukraine has received over $300B in Western military and financial aid

Although not a member of NATO, Ukraine has received substantial support from Western nations, primarily the United States and the European Union, totaling more than $300B in military, financial, and humanitarian assistance.

Testing assumptions about the war in Ukraine, one year later

Two years ago, policymakers in Washington made multiple predictions about the course of the war between Russia and Ukraine. One year later this site revisited several common assumptions about the war—for example, that Russia would swiftly defeat Ukraine—and asks several experts if they came true, or not. But things can always change.

The global nuclear arms regime has slowly eroded over the past few decades

Both Russia and the United States have withdrawn from key Cold War-era arms-control pacts. Russia's 2022 invasion of Ukraine marked a turning point, as it suspended its participation in inspections and data-sharing agreements.

A 1983 NATO war simulation provoked the Soviets to prepare for war

The "SNAFU" podcast, hosted by actor and comedian Ed Helms, explores some of the biggest blunders in history. Season one focuses on the 1983 NATO Able Archer military exercise, a war game that simulated nuclear attacks on the Soviet Union. The USSR mistook the exercise for a genuine threat and prepared its forces for war. Helms recounts this almost catastrophic event in world history with his signature humor.

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in terms of casualties, forces mobilized, and displacement of civilians.

Decisions at NATO are by consensus and must be unanimous

There are two strategic commands in NATO: one in Europe (Supreme Allied Headquarters Command Europe) and another in Norfolk, Virginia (Allied Command Transformation). The alliance is headed by both a military officer and a civilian leader.

Simulations of atmospheric transport have shown that radioactive material released from potential strikes to US nuclear missile silos would reach everyone in the continental US.

A legal scholar argues that the existing war powers framework may collapse in the event of a major power conflict

The legal tests presidents have used to avoid seeking congressional authorization were designed for weaker adversaries. This piece argues that those tests fail against similarly armed competitors, where even limited strikes risk significant escalation, potentially triggering a constitutional crisis over who has the authority to respond.

Much of the Global South responded to the Russia-Ukraine war by pursuing a strategy of 'active nonalignment'

Boston University scholar Jorge Heine suggests that countries across Africa, Asia, and Latin America are avoiding taking sides between Washington and Beijing—viewing the rules-based order as increasingly unresponsive to the needs of developing nations and considering the West's framing of the war irrelevant to its own interests.

Nearly 90% of the world's 12,187 nuclear warheads are held by Russia and the United States.

Russia's invasion of Ukraine accelerated fractures in the rules-based international order

This piece examines how the Ukraine conflict intensified underlying divisions in the global order—between Western democracies and the Global South, and between rule-of-law norms and great-power politics.

Experts argue that nuclear war is more likely than is commonly believed

The podcast highlights that many of the world's roughly 12,000 nuclear weapons—capable of triggering global collapse and nuclear winter—remain on high alert. Experts warn that this status, combined with limited public awareness, makes nuclear war disturbingly plausible.

Wartime conferences exposed cracks in the US–Soviet alliance

At the Tehran, Yalta and Potsdam Conferences, Allied leaders coordinated WWII strategy—but deep disagreements over postwar Europe foreshadowed the Cold War. The USSR’s push for influence in Eastern Europe clashed with US and British calls for self-determination.

Vladimir Putin was the first world leader to call Bush after 9/11, and visited the US two months later.

The 1955 Warsaw Pact was the Soviet Union’s answer to NATO

The pact included Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, Romania, and the USSR. The pact established collective security and a joint military command between the member countries.

Russia's private military force, explained

Not all participants in the Russian/Ukraine war are enlisted or drafted soldiers. Some, like the Wagner Group, are private mercenaries. But their reach extends past Russia and Ukraine's borders. This eight-minute video explores the activities of this shadowy company and how they aid Vladimir Putin in his military endeavors.

The last remaining US-Russia nuclear arms treaty expired in February 2026

The New START treaty, which capped US and Russian strategic warheads at 1,550 each, expired on Feb. 5, 2026. Without formal limits, fears of a renewed arms race are rising, as both nations could deploy more weapons while follow-on talks continue.

The Cold War (1947-1991) prompted the birth of NATO and the Soviet Warsaw Pact

The geopolitical rivalry between the United States and Soviet Union was considered “cold" because the two countries never directly engaged in military combat during the time period. This page from the Kennedy Presidential Library outlines the causes and major events of the early Cold War.

After it was banned from Eurovision, Russia resurrected its Cold War-era version

Russia was barred from the Eurovision Song Contest following its 2022 invasion of Ukraine. In 2025, President Vladimir Putin announced the revival of Intervision, a similarly structured song contest that the Soviet Union had organized throughout the Cold War.

Watch two Russian jets damage US drone over Black Sea

The Pentagon has released footage that appears to show a Russian aircraft intercepting a US Air Force drone in international airspace over the Black Sea.

Proponents argue that abandoning the rules-based order risks a return to the chaos that led to 2 world wars

Brookings scholar Robert Kagan warns that if China and Russia gain regional dominance, the world could return to the unstable conditions of the late 19th century—the same chaos that led to two devastating world wars.

Russia controls about 20% of Ukraine's territory

As of February 2026, Russian forces occupy roughly one-fifth of Ukraine, including Crimea and large parts of the Donetsk, Luhansk, Zaporizhzhia, and Kherson regions, with front lines largely unchanged for months.

A deep dive on the weapons being used by both sides

From ballistic missiles to armed drones, Russia’s invasion of Ukraine is proving the devastating power of modern weaponry. This infographic illustrates and explains the uses and effects of the weapons of choice for both sides of the conflict. Tactics are also explored in regards to their efficacy and consequences, with expert commentary added.

A primer on the president's nuclear football

During the Cold War, the United States and the USSR were forced to prepare for a nuclear strike at a moment's notice, leading to a new innovation: the so-called "football" (known as the chemodanchik in Russia), a bag containing nuclear strike plans, authentication codes, and likely a communication device, which attended the country's leader wherever they went. This easy-to-read piece breaks down the history and lore around the high-stakes quirk in nuclear governance.

A timeline of Russia-North Korea relations

North Korea and Russia have often had aligned interests, yet their relationship has experienced many highs and lows. Al Jazeera’s explainer outlines the key events defining Russia-North Korea relations. Russia and North Korea were allies during...

The rise of Vladimir Putin

Vladimir Putin's rise has been unprecedented. Over the years his actions have taken him from being a spy in East Germany to president of Russia. Learn more about his rise to power and the means by which he achieved it in this brief yet thorough nine-minute video.