"War is an ugly thing, but not the ugliest of things: the decayed and degraded state of moral and patriotic feeling which thinks that nothing is worth a war, is much worse."

-John Stuart Mill

Thinking nothing is worth a war is not the problem the US has with war, historically.

Quite true, but the war at hand is clearly one of defense (for the Ukrainian side).

Maybe the same applied to the British Empire of John Stuart Mill’s time.

It took Pearl Harbor to get America involved in WW2.

Prior ~80% were against doing anything to resist Hitler that might result in violent conflict.

America was famously “isolationist” at the time, yes. Obviously one is talking about US policy after WWII and up until the present.

You have roughly a year and a half of news to catch up to. Start with European news.

Degrading the Russian military through a proxy war is the cheapest and safest way to defend our NATO allies in Eastern Europe. Regardless of whether Russia eventually wins or loses in Ukraine, their military capabilities are being shattered and will take decades to rebuild.

It is not cheap. It costs many lives.

It is incredibly cheap in terms of dollars spent by NATO to kneecap the Russian military and prevent future expansion.

The US spent trillions for decades preparing for this sort of fight, all the way up to Ronald Reagan’s Star Wars stuff… and it turned out that something like 20% of one year’s US military budget (and some very brave, determined allies) does the trick.

Cheap for the USA. It's for the Ukrainians to decide whether the cost in lives is worth paying. As long as they're willing to keep fighting there's no downside for us in supplying weapons.

If US and NATO countries did nothing and Ukraine would lose the war, next step Russia would attack Poland or Baltics, and China would attack Taiwan.