The phrase is red meat for the right wing. I suppose it is called red meat because they eat it up. In other words, it is supposedly something that appeals to them politically.
Thanks to RonBee and Tdol, you know these idioms stuff, they are so funny. It is very interesting to study. I laugh when I saw your explanations. How come you two and Rep. Lofgren know so much? Do your parents spoke at home when you were kids? (Immigrants' children would have some disadvantages here because either we don't know or speak at home. Of course, this can be made up.) BMO
Thanks. We will never figure that out literally. Come to think of it, many idioms are related to "food." Just exactly is "eat your heart out?" It looks very offensive and I am still afraid of using it although I kind of know it vaguely. (Some native speakers use idioms more than others.) BMO