Do the best one can under given circumstances, as in Since he can't break the contract, Bill's making a virtue of necessity. This expression first appeared in English in Chaucer's The Knight's Tale: “Then is it wisdom, as it thinketh me, to make virtue of necessity.” Also see make the best of.

To pretend that one is freely and happily doing something one has been forced to do: “Once the mayor was forced by the voters to cut his budget, he made a virtue of necessity and loudly denounced government spending.”