The Supreme Court of Canada has shot down Prime Minister Stephen Harper's hopes of a quick fix for the scandal-plagued Senate.
The top court says Harper's plans to impose terms limits on senators and to create a election process for choosing nominees can't be done by the federal government alone.
It says the reforms would require constitutional amendments approved by at least seven provinces representing 50 per cent of the population - a process fraught with political landmines which Harper had hoped to avoid.
Harper has threatened to abolish the Senate if his reform plans are stymied.
But the Supreme Court has set an even higher constitutional hurdle to get rid of the upper house altogether: unanimous consent of all 10 provinces.