The US armed forces training in guerrilla warfare in North Carolina - Seems like the US fears an invasion on American soil

[SQ8]

An invasion of the US is pretty much suicide. Even if China succeeds, and by some chance nukes aren't used, any invading force would never recover from the damage dealt.

These exercises are to simulate urban insurgent warfare, because the US expects its immediate wars to all involve facing major urban insurgencies, similar to what it faced in Iraq.

How about asking our resident simulation expert @SQ8 to see how a Chinese invasion of the US would go.

Every other fiction published in the US talks about it being invaded - Red Dawn being the OG. However, it depends on what invasion is being referred to and what scope?
The amount of land the US has and the strategic depth it has in both equipment and industrial base means it can lose all of florida or california and still churn out similar capacity.

The US is still “invaded” daily with Illegal immigrants but in general the detection capability around the US coast and intelligence capabilities means the only real possibility comes from the South. However, Mexico is the US buffer state so at the end no one is touching this island beyond the small scale terror or crime based attacks.