The OP probably thought of defense in the narrow sense as "the action of defending against or resisting an attack", and not in the broader sense defined as "we’re going to travel halfway around the world to kill a million people because that’s who we are". A common mistake.
Not because “that’s who we are.” That’s a ret*rded retort. You go halfway around the world because you want to protect your friends and your nation’s interest.
Wouldn’t you do that to protect your family and your home, now and into generations? I think I know the answer.
That depends greatly on which interests you allow to be defined as "American". The vast majority of American people would have preferred not to be involved in most of our foreign adventures. The rich and powerful thought differently. Is our citizenship determined by the size of our bank accounts?
This is factually incorrect. Here are the estimates for the rates of support for each conflict at the beginning of the conflict:
- Iraq (Gulf War): 75-80%
- Iraq (2003): 65-76%
- Syria: 35-50%
- Vietnam: 65-75%
- Iran: 42%
Alexander Hamilton wrote that governance should involve people with “wisdom to discern” and “virtue to pursue the common good”. The US is not a direct democracy; it is a constitutional republic. The definition of what constitutes American interests is literally whatever the United States federal government says it is.
I'm probably going to get flagged for this, but here goes anyway.
Russia absolutely has reason to not want Ukraine to join NATO. I'm not condoning the invasion, but I say it absolutely makes sense for Russia to carry it out. Not a reason to commit war crimes, or to cause any more suffering than necessary, but from a national security perspective it makes sense to want to disrupt the process of Ukraine joining NATO.
Only if you accept the hidden assumption that Russia is an antagonist toward the rest of Europe. Otherwise the common "national security" justifications make no sense, because Russia benefits immensely from other NATO members investing resources into the development of institutions in newer member states.
A former Russian foreign minister has labeled NATO "free-of-charge security" for Russia, because NATO membership requirements turn a country into a stable and predictable place. The best neighbors Russia has are in NATO, and much of that stability is directly attributable to their membership.