Complex sentence: Under the Swiss Federal Constitution, the mode of election is left to the cantons, the proviso being that it must be a democratic method; however, all cantons now provide for the councillors to be chosen by popular election.
Split into simpler sentences: Under the Swiss Federal Constitution, the mode of election is left to the cantons, the proviso being that it must be a democratic method. However, all cantons now provide for the councillors to be chosen by popular election.