Excellent warning! What if the it was only a sham marriage for the foreign wife, but not the American husband?
Probably good to include these details in the prenup. I hope it can cover this.
A prenup would be an excellent idea, and many of the more honorable wife candidates will lead with this.
A sham marriage would be a sham marriage for both parties if it is proven that both parties knew it would be a sham, such as when a payment was involved.
In the past, they would only go after the foreign wife (or foreign husband), but now they go after both the American and the foreign members of the marriage.
It seems like the authorities realized that also penalizing the American half of the "marriage" exerted a stronger inhibitory effect.
Since the sham nature of the marriage is the illegal part, any provisions to that effect in a legal contract would render the contract unenforceable.