I've googled around and even tried to find the answer in the RFC to this one.
For this question, let's assume DKIM will always fail and leave it out of the picture.
If the DMARC policy is
p=reject and the SPF is configured to SoftFail (
~all), should the recipient reject the message in the event of a SoftFail?
p=reject only reject the message in the event of a HardFail.