The reference to Nazgûl is to the Lord of the Rings:
"Scott Walker" refers to the tea-party governor of Wisconsin, the one who is trying to remove many collective bargaining rights from state workers in Wisconsin.
Nazgul Walker is not just a tea-partier. He is also pretty extreme in his anti-abortion views, as in "nobody could be more extreme." From last fall's election campaign:
In a gubernatorial campaign largely centered on jobs and the job performance of the candidates, Democrat Tom Barrett has injected abortion into the debate, using a stark TV ad to take aim at his opponent, Republican Scott Walker.Bolds are mine.
A couple identified as Lana and Mike appear on the screen. Mike says their teenage daughter was brutally raped. "You can’t imagine what she went through," he says. "That’s why politicians like Scott Walker make me so mad."
The screen goes black. Then as Mike continues, the words he says also appear on the screen:
"Scott Walker wants to make abortion illegal, even in cases of rape, incest, or to protect the life of the mother."
...
We asked Jill Bader, Walker’s campaign spokeswoman, about Barrett’s ad and she said it accurately states Walker’s position.