The four week old war in Ukraine is reaching a critical turning point. Fierce Ukrainian resistance has stalled the Russian war machine’s advance thus ending any hope of a swift and easy victory. The Zelensky government remains in power and Ukraine remains a sovereign democracy.

The Ukrainian battlefield successes do not mean that Putin will seek a meaningful exit ramp and conduct serious negotiations to end the war. Instead, the increasingly angry and desperate Russian leader may view a settlement as a sign of weakness and a threat to his grip on power. The Russian propaganda machine is now dropping hints about launching a wave of cyber attacks, deploying chemical weapons, and even breaking the nuclear taboo by detonating a tactical nuclear weapon.

Each of these three types of escalation raises grave questions for President Biden and NATO leaders holding an emergency meeting in Brussels: How will NATO respond if Russian hackers disrupt Poland’s power grid? Would this prompt Poland to invoke NATO’s Article 5 that would require a unified NATO response? What if Putin uses a chemical attack to force the besieged city of Mariupol to surrender? Would this cross a red line that would galvanize global outrage that would force NATO into a military response? And finally, what if Putin uses a tactical nuclear weapon to destroy part of Kyiv and force the Ukrainian government to surrender? Would this create a nuclear crisis that could escalate into a third world war?