Yes, and the hard part is getting the establishment to allow them to build that trust and support instead of stifling like the classic American leftist example of Bernie

Relevant xkcd

Specific to elections: provide a principled left wing candidate with a platform that people can hear

For real substantial change: by taking away power from the powerful and giving it to the people

Most people agree with most leftist ideas (at least in theory), they’ve just been misinformed about what those ideas are and their true practicality

This seems to reinforce the idea of centrism being a losing strategy