OTTAWA—As an election was set to kick off, Liberal leader Michael Ignatieff moved swiftly to quash Harper’s line of attack that he would form a politically illegitimate “coalition’ with “socialists and separatists”—a line Conservatives repeated in the Commons on the day the government was defeated.

In a statement, Ignatieff flatly declared: “We will not enter a coalition with other federalist parties.”

“In our system, coalitions are a legitimate constitutional option. However, I believe that issue-by-issue collaboration with other parties is the best way for minority Parliaments to function. We categorically rule out a coalition or formal arrangement with the Bloc Quebecois.”

Ignatieff said “whoever leads the party that wins the most seats on election day should be called on to form the government.”

“If that is the Liberal Party, then I will be required to rapidly seek the confidence of the newly-elected Parliament. If our government cannot win the support of the House, then Mr. Harper will be called on to form a government and face the same challenge. That is our Constitution. It is the law of the land.”

It was the clearest answer the Liberals have given on a question that has dogged the party since 2008 when then-leader Stéphane Dion and NDP leader Jack Layton signed a pact to offer a governing coalition with the issue-by-issue support of the BQ.

Harper managed to survive that political crisis by suspending Parliament and bringing down a new budget that promised stimulus spending for an economic crisis.

All three parties united Friday in a vote on a Liberal motion that cited a committee’s recommendation that Harper’s government be cited for contempt for failing to fully document the costs of its combat jet purchase, anti-crime agenda, and corporate tax cuts.

It set the stage Saturday, when the Conservative leader drove across the street from 24 Sussex Drive to Rideau Hall on a cold, sunny Ottawa morning with wife Laureen to ask the Governor-General to dissolve Parliament.