THE CANADIAN PRESS -- OTTAWA -- The country's top court has declared that prosecutors have the right to renege on a plea bargain that would have allowed a woman to plead to careless driving in a deadly crash.

The Supreme Court of Canada was unanimous in its decision, the first time the justices have ruled on the discretion allowed prosecutors in plea agreements.

The Alberta case involved Olga Maria Nixon, who was charged with impaired driving causing death and injury in a 2006 crash which killed a couple and injured their seven-year-old son.

A prosecutor concluded there were problems with the admissibility of the breath samples and agreed to reduce the charges to dangerous driving causing death and injury.

Further negotiation led to a deal for a plea of careless driving, a traffic offence. But the deal was quashed by senior Alberta justice officials, which made Nixon's lawyers cry foul.

The Supreme Court has never ruled on whether a prosecutor can cancel a plea deal. But it has looked at other cases involving the discretion of prosecutors.

"So long as the proceedings are ongoing, the Crown may be required to make further decisions about whether the prosecution should be continued and, if so, in respect of what charges," Justice Louise Charron wrote for the majority.

Nixon was charged with impaired driving causing death and injury in the tragic accident in a small town north of Edmonton.

She drove her motor home through an intersection, fatally ramming the couple's car, and rendering their child an orphan.
Nixon's blood-alcohol level was triple the legal limit.

A prosecutor concluded there were problems with the admissibility of the breath samples and agreed to reduce the charges to dangerous driving causing death and injury.

The prosecutor was also concerned that eyewitness evidence of the motor home driving erratically was not strong.

That led to a deal for a plea of careless driving — a traffic offence carrying an $1,800 fine — in return for dropping the criminal charges.

The Alberta attorney general's office determined that agreement was contrary to the administration of justice and withdrew it.

An assistant deputy minister concluded that the prosecutor's assessment of the evidence was flawed.

Nixon's lawyers then argued that the Crown's repudiation of the deal was a violation of her Charter rights. The trial judge agreed and ordered the Crown to proceed with the lesser charge.

The Alberta Court of Appeal handed down an unanimous decision that upheld the prosecutor's right to cancel the deal. Justice Marina Paperny rejected the defence argument that the plea bargain was akin to a binding contract.

The Supreme Court agreed with that decision.

Charron noted that it must remain a rare occurrence that prosecutors find themselves having to repudiate a plea resolution. She said defence lawyers would lose confidence in the deals they negotiate with "front-line Crown counsel" with whom they work daily.

"All Attorneys General who have participated in this appeal agree that a plea agreement should only be repudiated in exceptional and rare circumstances. However the lawyers' undertaking analogy can only go so far on the question that occupies us," Charron wrote.

"As a result, the argument that a plea agreement can simply be characterized as a contractual undertaking must fail."
Nixon will now face a trial on the criminal charges.

It was not immediately clear whether Alberta prosecutors would exercise their discretion to retry the five-year-old case.