Peggy Olson on Mad Men is many things: Brilliant copywriter. Plaid enthusiast. Slumlord. At least that’s who she is in 1969. But who would she be today? Elisabeth Moss tells Rolling Stone she has someone in mind — someone brilliant and independent and successful and chic as hell. “I was watching The Good Wife the other night, and I was looking at Diane Lockhart [Christine Baranski],†she says. “I was actually watching her last night, going, ‘That’s who Peggy would be.’ This strong woman who’s sort of at the top of her game. I think that’s who she would be, but in advertising instead of law.†Diane is a pretty fantastic choice for future Peggy, given that Diane is baller enough to have been on the short list for the Supreme Court, and both women do have a history of falling for men who have an affinity for firearms …