Yeah that's what I was wondering, initially I even went so far as to say "an Oscar" but it'll definitely be too controversial for that. I dunno, I think he could maybe just get a nomination (of course if he's actually any good in it), but you may be right, looking back on the oscars, there's very rarely many controversial lead roles that even get a nod.
Political parts that were nominated, aside from Lincoln (and that's hardly controversial), you have Morgan Freeman as Mandela, Langella as Nixon, Penn as Harvey Milk (won), Whitaker as Idi Amin (won), Washington as Hurricane Carter, David Straithairn as Edward Murrow (what has Straithairn become?!)... This is going back to the early 2000s. Maybe Whitaker was the only surprising one in that lot, but there was a huge wankfest over his performance that year anyway, and it's not that comparable to Assange.