Thank you for the question.
You described it extremely well, actually. It's called the election security architecture and the various players who contribute to the governance of that space.
It is correct that a call goes out to political parties, via a letter, to have candidates who can be security-cleared and who will then engage with officials during the election period.
I was around for the 2021 general election and was part of organizing those briefings with officials from the parties. Generally, the conversations were very educative, making sure that, if individuals saw issues that caused concern, they knew where to go and how to identify issues. Topics covered were foreign interference and what to look out for. Briefings were also given on what ideologically motivated violent extremism is, and on security. What is a security clearance? What does it mean? How does it operate?
The last thing those meetings were very instrumental for is this: They allowed the representatives from the parties a chance to ask any questions they wanted to ask. There was a range of questions asked. It was very much a free-flowing exchange. They had security clearances, so we were able to share information.