(Susan Walsh/AP)

You’ve probably heard of the “policy riders” that are proving one of the sticking points in the bill funding the government for the rest of this year. These are amendments that Republicans attached to the spending bill that have little to nothing to do with funding the government. They’re about keeping the EPA from regulating carbon and defunding Planned Parenthood and attacking the health-care law and a dozen other things. But now that they’re on the bill, Republicans are really committed to them. So the negotiations aren’t just about how much to cut, and from where, but about these extraneous, more ideological riders. And that’s made the negotiations harder and a shutdown more likely.

Similarly, Ryan’s budget adds a bunch of extraneous, ideological priorities into the deficit reduction talks. He privatizes Medicare, which costs money. He repeals the resolution authority in Dodd-Frank. He reorients our energy strategy away from renewables and toward domestic production of fossil fuels. He locks in the Bush tax cuts. Most of these decisions are largely unrelated to the deficit, and/or increase it. But they’re polarizing — Republicans love them and Democrats hate them — and by bringing them into the discussion, it’ll make it ultimately harder to come to a deal. Both sides are only willing to compromise on so much, and when you add a lot of items that should have been included in the first place, you run the risk of hitting people’s limits before you’re able to deal with the core issues.