New Delhi, June 2 -- GRAHAM PLATNER has weathered more scandals in six months than many politicians do in a lifetime. The Senate candidate from Maine (pictured) has faced controversy over a tattoo associated with Nazism and bigoted social-media posts from his past. Now he is in trouble over explicit messages apparently sent to women on Kik, a messaging app with a relatively young user base that is often associated with sexting. Mr Platner is married-and it was his wife who alerted his campaign to the behaviour last year, fearing it might become a political liability.

That leaves Democrats in an awkward position. Until recently, Mr Platner appeared to have secured the party's nomination. His main challenger, Janet Mills, a two-term Democr...