On May 18, the Ontario Finance Minister brought down a budget that may become a political watershed - and his government's Waterloo. As Mr. Sorbara read the budget under the watchful eye of Premier Dalton McGuinty, it became clear that the Liberal leader's solemn election pledge not to raise taxes or run deficits had been torched. The budget includes a new health tax of between $300 and $900 a head for all taxpayers earning an annual income of over $20,000, and mires the province's finances in red ink until the year 2008.

In the ensuing days, taxpayers' outrage flooded the airwaves and the op-ed pages, accompanied by the desperate cry of "what can we do " On May 31, after thousands of calls and emails from infuriated citizens, and after seeking legal advice, the Canadian Taxpayers Federation (CTF) took action - literally - and commenced legal proceedings against Messrs. McGuinty and Sorbara.

The CTF's lawsuit seeks to compel Mr. Sorbara to obey Ontario's Taxpayer Protection Act, which prohibits him from introducing a bill that increases taxes or imposes new taxes unless the government has first obtained approval through a referendum. The suit also seeks to hold Mr. McGuinty accountable for his breach of promise, based on the laws of contract and negligent misrepresentation. (There is evidence that the Liberals knew well before last fall's election that the provincial deficit was approaching $5 billion. Yet the Liberal leader still signed the CTF's Taxpayer Protection Promise, a contract in which he pledged to hold the line on taxes, and which was the key to his election victory.)

The lawsuit is not without potential criticisms. The first is that taxpayer money will be spent to defend the government's case. The CTF is confident that this will not happen, because the lawsuit is taken against the defendants personally, not against the Crown. When former Alberta finance minister Stockwell Day fought a defamation action in his personal capacity, a court held that he was not entitled to legal representation at taxpayers' expense. The same rule should apply to Messrs. McGuinty and Sorbara.

The second potential criticism is that a court case could expose taxpayer protection legislation as a toothless tiger - and that would hurt, not help, Ontario taxpayers. The CTF disagrees. The principle that taxpayers need this type of legislation to protect them from tax-happy politicians is not in question. But if the current law is revealed to be ineffective, it makes the case that we need better safeguards for taxpayers' rights.

Let us be clear: the CTF would prefer this battle to be fought in the legislature, not in the courts. Under our current system, however, a lawsuit is the only option taxpayers have. Ontario does not have recall legislation like British Columbia or California. Voters here cannot hold their government accountable between elections - and the result is that politicians feel they can break their promises with impunity.

Until now, that is. If this lawsuit is successful, it will do more than settle the legal issues surrounding the Ontario budget. It will send a message to all politicians that taxpayers are fed up with broken promises and are willing to fight back. And if our legislators aren't careful, they'll end up in their own version of Elba: a place of political exile where taxpayers simply don't believe a word they say.