Regarding poverty, the GOP is currently (roughly speaking) an alliance between working class whites and business interests. Economically, the business interest side heavily dominates GOP policy at the moment. As far as poverty reduction goes, if you believe in either government oriented safety net solutions or other collective type structures (eg unions), this current political relationship sticks out like a sore thumb as being very counterproductive towards poverty reduction. Unfortunately, it appears that tribalism triumphs economic policy as a motivating factor at the moment.
I will say an additional thought: With the recent vote in France, I am wondering if the situation is somewhat more dynamic and fluid than this paper lets on. The Netherlands and France were only mentioned in passing, but it seems like the recent result in France actually produced an "anti-establishment" movement that also happened to be "pro-globalization" and "liberal" (in the classic economic sense). This sort of "populism" doesn't seem to be reflected in the paper.
Keep in mind that under Obama, the relative wealth (percent share of aggregate wealth) of minorities and the white working class actually decreased.
While I have no doubt racist policies have contributed to the misfortune of some, when you look at wealth distribution in the US the problem is far bigger than most people think, and spans all races.