She borrowed from her 401k and is only paying interest ~18% back into it. She doesn’t have to report it as income as her campaign owes the money.
Sounds like credit card territory to me. At those interest rates and having never retired the debt her campaign will eventually pay back many times the principal. Since she runs her campaign fund and can say whether or not the principal should be retired it’s a scam. Sweet deal if you can arrange it but you would have to be a Dem to get away with it if you get caught.
It doesn't matter who OWES the money. It's who RECEIVES it that determines taxation.
It's an interesting question, though. The "donors" are giving money to her campaign. She is then, in essence, using the money to pay herself. Does the campaign contribution angle allow her to enrich herself tax free? I honestly don't know. But it seems like it should be taxable in that SHE is the personal owner of the account that benefits.