Russia is much weaker than we are, but they have nukes and you can never tell if they will decide starting a broader war with NATO is a good option to escape their Ukraine crisis problem.
Here's how they might justify war:
Vladimir Putin does not buy the notion that tough economic sanctions, imposed on Russia by US and its European allies, are merely a punishment for Russia’s policies toward Ukraine, its annexation of Crimea, and its support of separatist fighters in the East Ukraine. Earlier today, speaking to the representatives of the Federal Assembly in Kremlin, he claimed that “the crisis in Ukraine was just a formal pretext for sanctions.” He was confident that “If all this had never happened, any other excuse would have been created” as a result of the “policy of containment [of Russia] which was invented not yesterday, but has been held against our country for decades, if not centuries.”
Mr. Putin’s tough rhetoric reflects the fact that economic sanctions on Russia—and counter-sanctions by Russia toward the countries of the European Union—are from his perspective nothing more than a substitute for the old-fashioned wars. Indeed, they damage the economies of all sides without firing a single shot.
Putin has purportedly set a red line at Russia's membership in the SWIFT banking system on this issue:
Yesterday, the German newspaper Handelsblatt published an interview that has yet to be printed in any English-language newspaper with the head of Russia’s second largest VTB-Bank (Foreign Trade Bank), Andrei Kostin. Mr. Kostin stated: “Of course, there is a plan B [in the case of shutting Russia off from the SWIFT bank system], but in my personal opinion it would mean war—if this type of sanction will be introduced. America and Europe did that against Iran but with Iran at that time there were no diplomatic relations, only military containment… If Russian banks’ access to SWIFT will be prohibited, the US ambassador to Moscow should leave the same day.
On the one hand, this is just another example of why Russia can't have nice things.
But it is also dangerous. I've noted that sanctions aren't always an ineffective alternative to war. Sometimes sanctions are seen as so dramatic that they are little different than war--so the leap to escalating to war is mentally a small step.
And if Russia doesn't see red lines as mere rhetorical devices to avoid immediate action, but sees them as a trigger that requires action, we could seriously miscalculate our response.
Russia would lose a major war if we choose to fight despite the advantages that Russia would have by striking first and grabbing territory whose loss we just accept rather than do anything about it.
But we'd have a war. And even a winning war--while better than losing a war--is hardly ideal, you must admit.
And a war with a major nuclear power--indeed a power whose military power is dangerously concentrated in their nuclear branch--is dangerous territory even if Putin is completely rational.