Graham Platner was a walking time bomb long before the on-the-record rape allegation he denied this week. A Nazi tattoo, social media rants, rampant rumors about women: Many Democratic leaders privately feared the Maine Democrat, now their U.S. Senate nominee, could be trouble. But they rationalized their delusions and denialism until it was too late. Now the party has few, if any, good options in one of the nation's most important Senate races. Why it matters: Platner's rise and fall shows a