In wake of Defense Minister Avigdor Lieberman's surprise resignation yesterday, the country seems headed to elections. We must put an end to this political instability. And it can be done. For years, Israel's system of proportional representation has led to political fragmentation and instability, undermining the capacity of successive governments to govern effectively. This is not a question of left vs. right: establishing a system with two large political parties will encourage both to move closer to the center and represent the interests of Israeli society as a whole.