And don’t forget..they have to show ID.
If you are not on the voter’s list published by Elections Canada, you need acceptable ID such as a photo Operator’s ID or Provincial photo ID card to receive a ballot.
Canadian T1s (I believe your equivalent is a 1040?) have a box to check for Canadian citizens if you want to allow the Canadian Revenue Agency (equivalent to your IRS) to share your addy and DoB with Elections Canada. Also, new citizens can check a box on their citizenship application form, allowing their addy and DoB to be shared with Elections Canada.
With this system, I believe that there is the possibility of non-citizens voting because no birth certificate is required nor a certificate of citizenship required. That said, because of the requirement for acceptable photo ID, it likely minimizes the number of non-citizens voting. While someone could vote in multiple ridings, the information that one ID was used in multiple locations would eventually raise alarm bells and that person would face criminal charges. The effort required for massive fraud is so much more than with electronic voting. The downside of paper ballots where you mark an ‘X’ beside your choice, is that in a country the size of the US, results would not be known as quickly as they are now.
In Canada, the gerrymandering occurs when ‘ridings’ or ‘constituencies’ (your ‘Congressional Districts’) are redistributed due to demographic changes based on the decennial census. Of course the political party in power has a greater say in such redistributions. Of course that can also happen in the US or any country.
One advantage I feel that Canada and ‘Westminster’ style democracies have over the US is that at election time, only the ‘Minister’ (your ‘Secretary’) changes. The ‘Deputy Minister’ and all those of lesser rank are civil servants and usually are not replaced with a change of government, so there is continuity. On the downside, unfortunately the BBC series ‘Yes, ‘Minister’ and ‘Yes, Prime ‘Minister’, while very funny, are close to the truth. It can be difficult to work with an entrenched bureaucracy.