A court injunction Tuesday suspended Alberta legislation that would enable a provincial oil boycott against British Columbia (BC) if the BC government blocked construction of the Trans Mountain Pipeline expansion.

The Federal Court of Canada ruled that the legislation, known as the “turn-off-the-taps bill,” could only be used if a complete trial ends in a verdict that the Alberta government has constitutional authority to interfere with deliveries.

No date has been set for a trial. The constitutional dispute is expected to be long, with both sides liable to pursue the case through the Canadian Federal Court of Appeal and finally the Supreme Court of Canada.

BC Premier John Horgan, who opposes the pipeline project on environmental grounds, called the injunction a relief. Trans Mountain delivers most BC crude oil and refined products supplies from a storage and trading hub at Alberta’s capital, Edmonton.

Alberta Premier Jason Kenney, a pipeline champion, said the contested legislation could eventually be amended to comply with the outcome of the court case. By nearly tripling capacity to 890,000 b/d from Canada’s top natural gas user, Alberta thermal oilsands production, the C$9 billion ($6.8 billion) expansion would transform Trans Mountain into an export conduit via ocean tankers in Vancouver Harbor.