The Alberta government is invoking the Charter’s notwithstanding clause in back-to-work legislation that will force public school teachers to return to class after a three-week strike, a move that organized labour leaders said could cause an “unprecedented response” by unions across the province.

If passed, the bill would use the notwithstanding clause, which allows governments to shield legislation from Charter challenges in court, to override Alberta teachers’ Charter right to strike or bargain collectively.

The decision to invoke the clause – a measure rarely taken by governments and even more infrequently used to end labour disputes – could lead to broad labour action in Alberta.

Last Friday, the Alberta Federation of Labour warned Premier Danielle Smith that using the notwithstanding clause would “escalate the situation from a confrontation between your government and the teachers to a confrontation between you and the entire Canadian labour movement.”