I have received and will be accepting an offer for a position in Switzerland that requires me getting a work visa (the employer is helping with this). While there's never been a case of someone in my position being declined this visa, this process takes at least 3 months, and there's still a possibility that I would not be able to start this job if the visa declined.
At the same time, I have other offers from employers in the US where a visa would not be an issue. While I feel that I should let these other employers know I'm accepting another offer, I don't want to be in a situation where if my visa is declined, I have to start my job search from scratch. Additionally, I imagine it is poor form to come back to an employer you previously declined and say "just kidding that other thing didn't work out."
What are my options here? I want to be respectful of these other employers needing to fill their positions, while remaining flexible in the event that my visa doesn't go through.