1) It looks at Ukraine's importance economically and concludes it's not worth it. The reality though is that it's really more about stability with our EU trading partners. If Ukraine falls to Russia suddenly we have to start worrying about supply chains and the economy of Poland, etc. Ripping away the buffer between western and eastern europe will have economic implications. 2) The US' involvement in both cases won't necessarily be similar. It's highly unlikely IMO that we will end up fighting russia directly with US troops. It's pretty clear now that the US approach to Ukraine will be at best arming ukranians and providing indirect support. It's far more effective in Ukraine to make invasion expensive and not worth it than trying to outright push back the Russians out of Crimea too. Between a combination of costly conflict, sanctions taking a toll on the Russian economy and enough resistance, it soon becomes untenable for the Russians to continue. Or at least that's the hope. 3) With Taiwan, the problem is that the PROC is basically increasing risk in the region to the point that with enough time people will start diversifying away from taiwan. We already see this with TSMC starting to build US fabs and Intel now investing heavily again in the domestic US. This doesn't change things in the next 3-5 years but on a longer horizon it does mean Taiwan's economic relevance does become more questionable. The PROC can wait as long as it needs for this to happen.