Obviously, but I think you're wrong and that that position is absurd.
Events never got beyond negotiation.
Kirk was authorized to take "whatever steps are necessary" to stop the Klingons from using Organia as a base, but he only took certain steps. Namely, he laid it all out to the Organians when he spoke to council. Kirk was inflexible and insistent in the negotiation
about a Federation presence on Organia only because the Klingons would have invaded in the true sense of the word. In fact, the Organians agreed that Kirk was genuine in his concern, while at the same time denying that Federation involvement was necessary. Then, the Klingons arrived.
We'll never know how things might have played out if the Klingons hadn't arrived when they did. I'll concede that one of the possibilities might have been invasion in true sense of the word, but only with the Enterprise
and/or other Federation ships safely in orbit at least long enough to beam down troops (infantry).
Now, if you want to argue that Kirk and Spock engaged in guerrilla activity on Klingon-occupied Organia, that's a different question, and they did, and, by the way, with phasers returned to them by the Organians. But that's not "invasion", either.
On the other hand, if, in the first place, Kirk had beamed down with a platoon of armed red shirts, "invasion" might have been the thing to call it. But Kirk was sensitive to that, and only he and Spock came. Kirk made peaceful proposals to the Organians devoid of euphemism, and again, the Organians regarded him as genuinely concerned, even if misguided.
"Invasion" is much more apt in The Enterprise Incident.