system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is a countries military strength is measured?

Followup: What makes America the worlds superpower?
gpt
There's not really 1 measure, it depends what the military is intended to be used for. Countries like Israel, Taiwan, South Korea, all these countries have a military built around immidiate defense against known enemies, they don't intend to go far from their own country. Or there are countries that have force projection in their priorities (the US) who want to be able to fight overseas


Then it also depends on what role it will play, Ireland doesn't really have much need to repel invasions or stop blockades, but they want to contribute to peacekeeping efforts. This means they probably don't have that much heavy firepower. As opposed to South korea, Taiwan, Israel, these countries have neighbours who want to take them out, powerful neighbours, and they know that victory isn't garenteed (as opposed to the US who knows no-one can invade them). So these countries will have a lot more heavy firepower, they might need it.



On your point about the US, because of money, they spend more on defense then the next several countries combined, there's a lot of talk about how the US defending Taiwan would go down, the views are split and this shows how strong the US is, why does this mean they are strong? Because in a theoretical war they have good odds of defeating a country with 4 times their population in that countries backyard. Remember that Taiwan is just off the coast of china, and the US still has good odds of winning.

What is it that the US spends money on, everything, they have good gear (not always the very best but always good) and they have a lot of it. And their ability to move troops/their navy, troops and tanks and planes are useless if they are in a base at home, the US has the ability to send them all over the world. Carriers too are important, they allow the US to quickly intervene in a war, they can instantly launch massive air and missile attacks on enemy troops within a very short time. The sheer firepower of just one carrier group could change the outcome of almost any war.



tldr; money spent, troop numbers. No best way since not all armies are built to fight the same wars.