Word for “they couldn't do it even if they wanted to”?

Question

If I were to say something like:

• "They couldn't have done X."
• "They're incapable of having done X."
• "It's not possible that they did X."

It can be interpreted in one of two ways:

1. They're morally/psychologically incapable of doing X (like I'm physically capable of murdering someone, but I'd never be able to bring myself to do so).
2. It's physically/logistically/biologically impossible for them to have done X (like it's impossible for the government to fake the existence of the Moon).

Is there any single word which will convey meaning #2, so I won't have to use some wordy phrasing like "they couldn't do it even if they wanted to"?

Answer 1

Physically impaired

1. Weakened or damaged.

Psychologically incapacitated

1. Prevent from functioning in a normal way.

Impaired and incapacitated can generally be used interchangeably too.

Logistically impractical

2. North American: Impossible to do; impracticable.

Also, [not] feasible

Possible and practical to do easily or conveniently.

Morally bound {to do [or not do] something}

bound³:

1.1. Obliged by law, circumstances, or duty to do something.

Source used: Oxford English Dictionary