The ongoing reporting and commentary in the popular press on hacking the elections has been frustratingly opaque and misleading because so many of the participants in the discussion have (either intentionally or through basic ignorance) conflated three very different problems:
1. Actual intrusion, compromise, and manipulation of computer systems involved in various stages of the election process, to include voter registration record systems, electronic voting machines, and vote accumulation tabulator systems.
2. Information operations to influence voter decisions using communication media, social media, real and fake news stories, etc.
3. Fraudulent voting schemes that involve arranging for seemingly valid votes by unauthorized individuals, such as the same person voting in multiple jurisdictions, successfully registering unauthorized voters with falsified voter registration forms, etc.
Harking back to a recurring reminder by @rslade to define the context in every discussion, case 1 uses the term hacker in its modern historical context of hacking into and manipulating computers, In cases 2 and 3 the term is used in a broader context of "fixing" an election through fraud.
I'd ask that any further discussion in this community maintain clear context on which of those cases you wish to discuss.