Dalton McGuinty is finding — like a Progressive Conservative predecessor, Mike Harris — that even powerful premiers are not above the law.

McGuinty has been told by two courts that a law brought in by the Conservatives in 2002 that gives farm workers the right to form associations, but not to bargain collectively with their employers over pay or job conditions, violates their rights and his government has 12 months to change it.

McGuinty has been asked quickly by New Democrats to assure he will not appeal the judges' ruling and said he needs time to think about it.

But the case resembles closely one Harris lost, on same-sex relationships, and it seems unlikely any attempt to persuade the judicial system to change its mind would be successful.

The Agricultural Employees Protection Act, 2002 (AEPA) was enacted by the Ernie Eves Conservatives in response to a Supreme Court of Canada having struck down a law Harris passed in 1995 that revoked the NDP's Agricultural Labour Relations Act, 1994, which gave farm workers the right to organize and bargain collectively but not to strike.

In more recent decisions, the Supreme Court of Canada held the Constitution's Charter of Rights and Freedoms, which guarantees freedom of association, allows hospital employees in British Columbia to bargain collectively and that province had violated this by passing a law interfering with collective bargaining.

The Ontario Court of Appeal has now reinforced this by striking down the AEPA, which allowed farm workers to form associations but lacked any mechanism for collective bargaining.

In the case with similarities involving Harris, the Supreme Court of Canada found the Charter requires provinces to give same-sex couples the same rights they give couples of opposite sexes living together.

Harris's government was opposed to providing these rights, but complied reluctantly. Harris said he considered marriage as "me, my wife and our two kids," although ironically he separated from his wife soon after and was seen with younger women.

To show he disapproved of the new Ontario law that was required, Harris gave it an odd, unwieldy title, An Act To Amend Certain Statutes Because of the Supreme Court of Canada Decision In M v H, while most laws have titles of only a few words — but he still obeyed the court.

McGuinty will not find it easy to comply with the courts' directions. There are arguments for and against giving farm workers power to form unions and negotiate collectively with employers.

They are among the lowest paid workers and many, particularly in agribusinesses such as mushroom plants and chicken hatcheries, work under dirty and dangerous conditions. A case can be made readily that they deserve higher wages and better conditions when compared to other workers.

A main argument against unionization over the years has been farms need employees who can work long hours when called on, particularly during harvesting, without restrictions that add unmanageable costs. This is true particularly of smaller, family farms, which are especially vulnerable.

Farms increasingly are big and in some ways like other industries, but many still are family businesses. Farmers also already are having difficulty competing against lower-cost produce from abroad, often subsidized by their countries of origin.

No government would want either type to go under, for the sake of those owning and employed by them and particularly at a time when job losses are the biggest issue in Ontario politics.

The Liberals do not want to risk losing votes in ridings still dominated by farmers, although these are steadily dwindling.

The Court of Appeal has given McGuinty 12 months to introduce legislation that will permit and protect the right of farm workers to set up unions to bargain collectively with their employers.

The court said the province cannot deny farm workers the right to collective bargaining on economic grounds, when it allows it to almost every other class of worker.

The judgment was written by Chief Justice Warren Winkler, the two judges sitting with him agreed, and the Supreme Court of Canada thought much the same way — it does not sound like a ruling that will be easily overturned.