Mearsheimer warns Russia may strike NATO countries and even consider limited nuclear use, which would be very bad for Europe and global security.

• Russia is still winning on the ground in Ukraine and has taken about 20% of the country, which Ukraine will not get back.
• Ukraine is hitting deep into Russia with drones and missiles, killing civilians and damaging oil refineries, and Moscow says it has had enough.
• Russia recently hit Kyiv harder than ever and warned European countries to pull diplomats out, signaling possible strikes on Western targets.
• The US used up so many Patriot missiles defending against Iran that it cannot resupply Ukraine, leaving Ukrainian cities wide open to Russian attacks.
• Russian elites argue they must restore deterrence with limited conventional strikes on Europe, and use a handful of nuclear weapons if that fails, because the West acts like it can hit Russia for free.

Outlook: The risk of Russian strikes on NATO countries is rising, and the nuclear taboo may be the next one tested if the West keeps helping Ukraine hit deep inside Russia.