The GOP must steer clear of guest-worker programs and legalization without citizenship. Two of the basic rules of democratic politics are: Don’t hurt your allies, and don’t give your electoral opponents a weapon to use against you. As House Republican leaders prepare to announce their immigration principles near the end of this month, they should be aware of both rules. Two policies they are considering endorsing — legalization without citizenship and a massive increase in guest-worker visas — could sabotage the GOP’s standing with its base while also closing off future electoral roads. Legalization without citizenship would split the base...