> Crimea agreed after the fact that the Russians were merely securing their own territory, correct?
Those are the results announced by Russia immediately after their military invasion, yes.
It doesn't mean those are the actual results, that the voting was actually done by "the Crimeans", or that the voting was free or fair. [1]
> If so, then there was no invasion.
No, even if the people of the invaded part of the Ukraine actually agreed after-the-fact, Russia unauthorized intrusion with military forces into what Russia had previously by treaties (in which it also agreed to respect and guarantee the soveriegnty and territorial integrity of the Ukraine, as part of a deal wherein the Ukraine gave up the former Soviet nuclear weapons on its territory) agreed was Ukrainian territory would still be an invasion. It doesn't retroactively become "not an invasion" based on events after the invasion occurs.
> If the Crimeans had voted no, would Russia still be there?
Those are the results announced by Russia immediately after their military invasion, yes.
It doesn't mean those are the actual results, that the voting was actually done by "the Crimeans", or that the voting was free or fair. [1]
> If so, then there was no invasion.
No, even if the people of the invaded part of the Ukraine actually agreed after-the-fact, Russia unauthorized intrusion with military forces into what Russia had previously by treaties (in which it also agreed to respect and guarantee the soveriegnty and territorial integrity of the Ukraine, as part of a deal wherein the Ukraine gave up the former Soviet nuclear weapons on its territory) agreed was Ukrainian territory would still be an invasion. It doesn't retroactively become "not an invasion" based on events after the invasion occurs.
> If the Crimeans had voted no, would Russia still be there?
Almost certainly.
[1] http://www.businessinsider.com/un-hints-russia-may-have-rigg...