David Orchard believes a plan to merge the Progressive Conservative party with the Canadian Alliance is doomed to fail, and he's going to court to stop it.

The twice-failed leadership contender and a group of Conservative members are asking the Ontario Superior Court to rule that leader Peter MacKay violated the party's constitution, and to block any merger.

In a news conference Friday at a Toronto law office, Orchard said the deal MacKay and Alliance leader Stephen Harper agreed to was a betrayal of the Tory party, and a recipe for disaster.

"This idea that we could unite the right... I think we're going to be dead in the province of Quebec, we're going to be dead in Atlantic Canada, and I suspect we're going to find out that Paul Martin is going to crush this new vehicle and we will have abandoned and destroyed the Progressive Conservative Party of Canada," Orchard said. "That's not what I want to see happen."

Orchard threw his support behind MacKay's leadership bid, but on the condition that MacKay didn't negotiate a merger with the Canadian Alliance.

Orchard's challenge says that MacKay doesn't have the authority to come to agree to a merger.

"They have suspended the constitution of the party," lawyer Sean Dewart said. "It's a coup. The only thing that's missing are the sunglasses."

Any individual party member – including MacKay – who wants to join the other party is free to do so, Orchard said.

"We want to stay and maintain the Progressive Conservative Party of Canada," he said.

MacKay and Harper reached an agreement on joining the two sides into the Conservative Party in mid-October, and now their memberships will vote on it.

The Tories will elect delegates during a Nov. 29 to Dec. 2 vote, who will in turn vote in regional ratification meetings Dec. 6. Those regional meetings will be linked by teleconference in a virtual convention.

The Alliance will announce the results of its mail-in ballot Dec. 4. Two-thirds of the Tory party must agree, while 50 per cent plus one of the Alliance have to be on board. The possible merger must be ratified by Dec. 12.