So while there are marmots around here they are no where near my garden. From what you describe I am wondering if raccoons might prefer sweet corn to flour corn. That would be a huge plus. No matter what though I am going to grow this gorgeous corn and see how it goes.
Unfortunately, raccoons like corn in the milk stage - and all corn goes through that stage as the ears develop.

To some extent, I think they (and deer, and birds) keep coming back once they learn that something they want is in the garden. So it is important to discourage them from entering (and tasting) initially. Electric fencing is effective to provide that discouragement.
In my rural garden, raccoons ruined my first corn crop, pulling down stalks & taking a bite or two from nearly every ear. I put up a fence with chicken wire low, and the first electric wire just above that, to keep animals from climbing over. It worked for a couple years. But to till the garden, I take down 2 sides of the fence - which then needs to be re-erected. I was late re-running the wire one year, only turning on the fence when damage to the corn began. It was too late; the raccoons, having tasted the corn, apparently put up with the shocks to get more (and this was a strong fence charger). After that, I made a point of getting the fence up & charged early, and never had another raccoon incursion.
I think that the local food supply is also a factor in whether or not raccoons will attack corn. My suburban gardens are fenced with welded wire to 6 feet, with chicken wire low to keep out rabbits. I know raccoons wander my property, because I've caught a few while trying to trap ground hogs. Although I've never used electric fencing there, the raccoons have yet to attack the corn. Not sure if that is because they get their fill from scavenging garbage locally, or whether they just don't like dry corn... but as the saying goes, don't look a gift horse in the mouth.
Oh, and deer have a good memory too. If they get stung a couple times early in the season, they remember. I can turn off the fence in mid-summer, and they will still avoid the wires. You still need to take measures to discourage them from jumping over though, they
will clear a 6' fence if they see a clear landing point on the other side.