Weird. Never heard of the short form "Carthago delenda est."
Anyway, the link you provided also doesn't know the form
"Censeo Carthago delenda est"
as you use it.
It only knows the full form
"Ceterum censeo Carthaginem esse delendam"
or two short forms:
"Ceterum censeo"
or
"Carthago delenda est"
Notably the citations in the end of the article, all use the accusative form (which may be why I only know that one from Latin school).
And to me your version still looks weird.
Censeo means "I think"
From what I remember one must follow that up with either a word like "that", as in:
"I think that (Carthago must be destroyed, for example")
Alternatively, one can use the "accusative plus esse" construct, which works without a conjunction word, as in:
"I think (censeo) Carthago (Carthaginem) to be (esse) a one to be destroyed (delendam)"
I think the "Carthago delenda est" only works as a full sentence, and must be connected with a conjunction word when used as a dependent clause.
But again - I could be wrong. Or, my former Latin teacher :-P Although I will take full credits for the mistake if indeed all forms are fomally correct.
Anyway, the Romansprobablydefinately used their language back in the day like we use ours - sloppily.
@Fyra: you sure? you sound sure
ETA:
I first didn't know what that was, because the term is completely different in German.
But YES, Latin had that. In spades. Basically, subjunctive mood was the hell you came into when you thought you had finally learned enough Latin to be passable. Luckily, modern languages have rationalised away some of that, but some are still hard enough, I guess. :-)