s.bernbaum
Mostly lurking
Yes, but keep in mind that the civ you declared war on will come after YOU.
However, if you don't have a common border with your new enemy and the AI in between is either at war with them or does not have open borders with them, the enemy AI will attack the AI in between in the first case and leave you alone in the second. Of course, you can also bribe the one in between to either join the war or cancel open borders, if appropriate.