By Luke Baker JERUSALEM, March 18 (Reuters) - As the dust settles on a dramatic election, the immediate questions are how Prime Minister Benjamin Netanyahu managed to stage such a fierce comeback, why the opposition fell short and what it means for Israel, the Palestinians and the world. Four days before the vote, Netanyahu looked all but out for the count, with the last opinion polls giving the center-left Zionist Union a four-seat lead - enough not only to win but potentially to form a governing coalition.