What makes you think that? I tend to disagree. The infrastructure damage to things that might effect voting are fairly localized. Further, I have no data, but I'd guess that the people in those affected areas would try double hard to get to the polls. I know those people, it's where I come from. But again, I have no hard data.
Those people are out of their homes, there are still rescue missions going on. It’s a big deal to get them voting in/for the next three weeks.
For those who have paid attention to the HAARP stuff and various weather manipulation technologies, a theory is that Michael was intensified and directed for just that purpose, primarily because the governor of FL is so pivotal in that huge swing state in presidential elections.