This is an interesting and incisive analysis of possible ways the U.S. could end up in a war with Russia. From Christopher Blattman at RealClearPolitics via zerohedge.com:
The Biden administration has worked hard to keep Russia from treating America as a co-combatant in Ukraine. But that doesn’t mean NATO isn’t deeply embroiled in the fight. The level of support is extraordinary and increasing, including sanctions, intelligence sharing, weapons transfers, and money. Add to that the ever-heightening political rhetoric: “The United States is in this to win it,” one US Congressman tweeted from Kyiv.
But nothing in international law stops Russia from changing its mind and treating the United States as an active party to the conflict. Instead of providing bright red lines, the conventions are fuzzy and subjective. The fact that Vladimir Putin hasn’t deemed NATO a co-combatant comes from a mix of murky international norms, strategic calculation, and luck.
At some point, that could change. Perhaps a Ukrainian military unit uses a long-range system from NATO to attack Belgorod, just inside the Russian border, and Putin orders his military to retaliate against a Western country. Or, as the torrent of heavy weapons to Ukraine grows, perhaps Russia decides that supply depots in Poland are fair game. We can imagine these scenarios by the dozen.
In all likelihood, however, none of these will come to pass. Fighting is ruinous, and so, as a general rule, countries do their best to avoid open conflict—especially one that could go nuclear. The costs of war also mean that (when they do fight) nations have powerful incentives not to escalate and expand those wars—to keep the fighting contained. This is one of the most powerful insights from both history and game theory, and the subject of my recent book, Why We Fight: The Roots of War and the Paths to Peace. War is a last resort, and the costlier that war, the harder both sides will work to avoid it.