Don't know of a single song, offhand [tho see below]: but isn't the folklore that John Gay's The Beggar's Opera [1728] was instrumental in bringing Horace Walpole down? And such a good piece of work in its own right that it goes on being performed purely for its entertainment value nearly 300 years later, when all the actual issues it satirises are dead and forgotten. And song's like "That was directed at me" still bite..., even if Walpole represented as a receiver of stolen goods and his opponents as thieves & highwaymen & pimps, no longer means anything to us at all.

And how about Joan Littlewood's {Mrs E MacColl's!} Oh What A Lovely War?

I remember Ralph McTell once remarking sadly that Streets Of London had done more for him than the people who were its subject ~ but who can tell, in the long term, what effect it might have? And will it still be sung? & maybe Ewan's Go Down You Murderers & Karl's Guns And Comics had some influence in the cap-pun debate. Who can tell?

~M~