“He feared a U.S. invasion” vs. “He feared U.S. invasion”

Question

It it accurate to say this?

He feared a U.S. invasion.

Or should I say,

He feared U.S. invasion.

I'm trying to figure out when to place "a" in front of the U.S. when U.S. comes with a noun like invasion/attack/sanctions. What is the difference?

Answer 1

I prefer the second option on socio-political grounds:

"He feared U.S. invasion"

Because, as opposed to an attack, an invasion is a drawn out process, and the indefinite article excessively encapsulates it. I would compare this to saying,

I fear an afterschool detention is in store for me

or

I fear punishment is in store for me

While my punishment could be a detention, the idea of punishment doesn't imply a finite action like a one-hour detention.

You don't lose any meaning between "a U.S. invasion" and "U.S. invasion" but, contextually, I imagine that a person who fears invasion does not only fear the finite action that occurs when borders are breached but the attendant occupation of the territory, which comprises a drawn-out and nearly undefinable period of time--perhaps, even a permanent condition owing to the leftover cultural and religious residue from the expelled invaders.

Answer 2

I'm trying to figure out when to place "a" in front of the U.S. when U.S. comes with a noun like invasion/attack/sanctions. What is the difference?

Why the U.S. specifically? Do I smell a political position there? :)

In any case,

What makes the U.S. (as a nation's name) a bit special is that it's hard to make into a differentiated adjective (vs. Europe/European or Canada/Canadian, for example).

Here's my knee-jerk for each of your mentioned words (sanctions, attack, invasion):

They feared U.S. sanctions. (Can't be done otherwise since 'sanctions' is plural anyway').

They feared a U.S. attack.

They feared U.S. invasion.

I don't think there's a general rule for these type of expressions; you'll probably have to learn them by idiom.