Yglesias asks us look at how Republicans already are opposing cutting any support for their core constituencies:
Basically the currently elderly, people living in rural areas, and people whose income depends on the military-industrial complex would all be protected from a drive that focuses specifically on domestic discretionary. Not coincidentally, these are many of the people inclined to vote Republican.
Besides the fact that Republicans are much better at demonizing Democratic constituencies (“Greedy teachers,” etc.), Republicans have been able to attach moral opprobrium for when Democratic constituencies effectively use the political system to enhance their welfare. Think of how Republicans talk about teacher’s unions. The fact is that everyone tries to use the government for pecuniary gain, and I don’t see how what moral distinction one can make between a grain farmer in Iowa supported by farm subsidies, and a teacher using collective action and labor laws to protect their pay and benefits. Both are contributing something useful to society and using government to ensure they get the best possible compensation for their work.