BERN - The summer session opens on Monday 1 June and runs to 19 June. In the middle, on Sunday 14 June, voters decide the Sustainability Initiative and the Civilian Service Act amendment. Later that week the chambers take the proposal to lift the 2017 nuclear ban. Mercosur is also on the National Council list.

Whips told members to expect a short temper after the ballot. Losing parties look for compensation. Winning parties look for a second helping.

A heavy month

Our opener is 1 June. The nuclear floor fight is 18 June.