"The United States is involved in a global "War on Terror".

A dictionary says that "involved" is an adjective. So in this sentence, I think "is" acts as a linking verb, and "involved" then is a predicate adjective, describing the subject, "The United States". Is this a correct interpretation? Or, is "involved" actually a past participle (verb form acting as adjective, correct?) and "involved in a global..." just a participle phrase, so this sentence is just making a statement with no linking verb involved?

Thanks for your time,

Anonymous"The United States is involved in a global "War on Terror".
"Is" is the only finite verb in the sentence, and by its nature is a linking verb.
It seems to link the whole participial phrase, rather than just the adjective. That is, the participle doesn't really function as an adjective.

Dictionaries often disagree on which participles are worthy of separate entries as adjectives.

But being so listed never disqualifies them from heading participial phrases.

Is the United States involved? (reply) Yes, the United States is involved. Is this an adjective? Probably.
Thank you! This helps a lot.