Five federal party leaders will face off in the first of two official election debates tonight in what may well be their best chance to sway voters before election day on Sept. 20.

With less than two weeks to go, millions of voters are expected to tune in for tonight鈥檚 two-hour French debate and Thursday鈥檚 English debate.

Liberal Leader Justin Trudeau, Conservative Leader Erin O鈥橳oole, NDP Leader Jagmeet Singh, Bloc Qu茅b茅cois Leader Yves-Fran莽ois Blanchet and Green Party Leader Annamie Paul will participate in both debates.

People鈥檚 Party of Canada Leader Maxime Bernier did not meet the criteria established by the independent leaders鈥� debate commission for participation.

Both debates, organized by consortiums of broadcasters, are being held at the Museum of Canadian History in Gatineau, Que., just across the river from Parliament Hill.

Ahead of the debate, the Conservatives will share how much their platform, which was released near the start of the election campaign, is expected to cost. The party is holding a technical briefing for the media at 4 p.m. eastern time on Wednesday.

The debates come as opinion polls suggest the Liberals and Conservatives are stuck in a tight two-way race, with the NDP and Bloc poised to determine which of the two main parties emerges victorious.

Last week鈥檚 TVA French debate, to which neither Paul nor Bernier was invited, appears to have done little to move the needle for any party.

In 2019, some 7.5 million Canadians tuned in to the English debate across all traditional and social media platforms while some three million tuned in to the official French debate.

Surveys conducted by the debates commission afterwards suggested that 鈥渢he debates were central to the electoral process,鈥� according to a commission report on the process.

鈥淥n balance, the debates played an important role in increasing engagement with the issues, leaders, and choices before voters.鈥�

That said, the commission reported that its surveys found no measurable difference in intended turnout or change in vote intention between Canadians who watched the debates and those who didn鈥檛.

Tonight鈥檚 French debate begins at 8 p.m. ET.

Topics to be discussed are climate change, the cost of living and public finances, Indigenous Peoples and cultural identity, justice and foreign policy, and health care and the COVID-19 pandemic.

The English debate on Thursday starts at 9 p.m.

The topics for that debate are affordability, climate, COVID-19 recovery, leadership and accountability and reconciliation with Indigenous Peoples.

鈥擳he Canadian Press