It may not come to that, if the bill is defeated.
Both Trudeau and NDP Leader Tom Mulcair are urging Prime Minister Stephen Harper to allow Conservative backbenchers to vote freely on the bill — although they acknowledge that seems unlikely.
The bill has been almost universally panned by federal and provincial electoral experts in Canada and by international experts as well.
Critics fear the reforms would disenfranchise tens of thousands of voters, erode the independence of the chief electoral officer, impede investigations into wrongdoing, give an unfair financial advantage to rich, established parties and undermine people's faith in the fairness of the electoral process.
The government has shrugged off all the criticism, maintaining the bill contains common-sense reforms that will prevent voter fraud, crack down on misleading robocalls during elections and stiffen penalties for those who break election laws.