Conservatives will undoubtedly seethe over Obama’s unilateral action. But once they exhaust their procedural objections, any substantive opposition to the policy itself is either cruel or dangerous.

On the one hand, conservatives could object to a codification of ICE’s existing practices. Under this argument, it’s not selective enforcement of the law that’s the problem, but explicitly telling immigrants who arrived in the country illegally that they’re in the clear. Keeping the law hazy would subject law-abiding immigrants to an illusory fear, supposedly discouraging migrant flows.

This is a deeply inhumane tactic. Their preference would be for millions of immigrants to needlessly live with the specter of deportation hanging over their heads. This would condemn them to living in the shadows and working in tenuous, often-exploitative conditions — even though immigration officials have no interest in deporting them.

The other objection — rejecting prosecutorial discretion outright — isn’t any more heartening. This would involve ICE pursuing every undocumented immigrant with equal zeal.