Political strategists are downplaying the importance of the debates, saying they're not "do or die," according to Conservative politico Line Maheux.
However, some pollsters called the debate critical for Liberal Leader Paul Martin, saying he had the most to lose, while Tory Leader Stephen Harper had the most to gain.
The leaders are more exposed in a debate than any time campaigning, Nick Nanos, president of the polling firm SES Research, said in a report in the Toronto Sun.
All four leaders kept a relatively low profile over the weekend in preparation of the big debate.
While there's always talk of the so-called knock-out punch, the leaders are mostly hoping to avoid any costly slip-ups and capitalize on any mistakes the others make.
Harper said he knows what to expect from the Liberals.
"My anticipation is the Liberal campaign will increasingly ... resort to fear and smear," he said.
The Liberals said they would simply highlight the differences between Martin and Harper.
New Democrat strategist Jamey Heath said the debates would serve as a reminder to voters that the party's leader, Jack Layton, is alive and well, despite claims by Martin that voters have only two choices.
Interest has been high among Canadians. For the first debate, more than 9,000 questions were received, said CBC spokesman Jason MacDonald.
For this debate, an editorial committee made up of representatives from several broadcasters sifted through the thousands of new questions to be put to the leaders.
This debate will be similar to the one last month in Vancouver. Leaders will be asked questions, and will not be allowed to talk over each other or go head-to-head on any issue or question.
