The "tyranny of distance" is always a problem for America:
When it comes to war, America is almost always playing an “away game.” The conflicts the nation has recently fought, and the defense activities it engages in, are in distant places. There is little reason to suspect this tendency will change anytime soon. Afghanistan and Iraq are both nearly on the opposite side of the globe from the continental United States, and much of the War on Terror over the past two decades has been conducted thousands of miles from U.S. shores. The nations that the 2017 National Security Strategy lists as being of particular concern—China, Russia, Iran, and North Korea—are not only themselves quite far from the United States, but the most likely areas of conflict stemming from these threats—the East and South China Seas, Eastern Europe, the Persian Gulf, and the Korean Peninsula, respectively—are likewise proximate to the potential adversary and quite far from North America.
Which in a way is good. No enemies seriously threaten the Western Hemisphere with conventional military power.
But it causes problems.
Overcoming this distance to war theaters imposes massive costs on
America that other countries don't have to pay. Moving and supplying those forces is much more complicated and expensive for America.
America needs far more material to reduce friendly casualties to sustain the will to fight far from home.
And distance affects America in other ways like placing limits on our warship designs, for example. American ships have to be able to cross oceans even before fighting. Many countries need only leave port to be in their combat patrol area. Those countries can build small and heavily armed warships.
The distance also means enemies can mass
power at the start of a war they initiate against forward-deployed
American forces. Striking a balance between supporting allies in peacetime against limiting losses should an enemy strike is difficult.
In college I started on a project in an independent study course using the Correlates of War power scores to account for the effect of distance on national power. But I ended up not going to grad school in political science. So I dropped that. It was only a few years ago that I finally threw out my 3x5 data set cards. Professor J. David Singer was great. He was obviously liberal. But I never feared being conservative in his class. That was college. I'm not sure what we have now.
But I digress (as I can!).
Do read all of the article.
Still, I'm not sure China necessarily has superior will to win a fight over Taiwan compared to America. One, China is more casualty sensitive than we think. Second, a battle for Taiwan isn't only a battle for Taiwan. Which raises the stakes for America. Third, as I've said, even the distance across the Taiwan Strait has a big effect on degrading Chinese power.
As an aside, the topic of America failing to anticipate Chinese intervention in the Korean War is real. But I recently read that the Chinese didn't want to go to war with America, but were pushed by the USSR:
When North Koreans and Chinese died in huge numbers for the Soviets. Which is interesting and a reminder that American and allied troops approaching the Yalu River in 1950 were not, themselves, the reason China intervened in the Korean War. Which runs contrary to the Cold War era assumption that America provoked Chinese intervention by appearing threatening to China. In fact, the Soviets had to push China to intervene.
Which still causes some Chinese resentment toward Russia. So we may have read China correctly but didn't realize who we needed to anticipate.
