If you look at how the election period is affecting Franken and the decision...I would suggest that he might wait until March.
The other senator...Klobuchar...is up for election in Nov of 2018.
Franken has to leave prior to 29 May 2018...if not, that gives the Governor the ability to appoint someone, and the special election is not until November 2019. The Gov is a Democrat so it’s a sure thing he’ll pick a Democrat.
I’ll go and even predict that the Gov (Mark Dayton, age 70) might go and select himself to fill out the term, and run in November.
Isnt mark dayton Gay?
If the governor of Minnesota was a Republican Franken would not be resigning.