"Το" here is not an article, of course. It's the weak form of αυτό in acussative case. When using the imperative, the pronoun comes after the verb, contrary to the indicative where the pronouns come before the verb. So Πάρε το απόφαση is "Take it as a decision (if that can be told), decide it". In the meaning of "Decide it that things are that way and cannot be changed, deal with it!"