Rep. Raul Labrador, R-Idaho, a leading voice for tea-party conservatives on immigration, has suggested that even the probationary legalization of illegal immigrants should wait until some enforcement mechanisms are in place. “We have to have enforcement triggers happen before anyone receives any kind of legal status,” he said Wednesday. “Certain objective triggers that we can measure.”

Labrador is walking a tightrope between the tea-party House members who follow his lead on immigration and the immigrant-friendly lawmakers with whom he is trying to strike a deal. The two groups don’t speak the same language. For hardcore conservatives, only tough enforcement benchmarks could give them enough comfort to support the legislation. “We cannot simply legalize 12 million people and enforce the laws later,” Senate Judiciary Committee ranking Republican Chuck Grassley, R-Iowa, said Wednesday.

But Labrador’s suggestion is a deal-breaker for immigrant advocates and Democrats. “Whoever’s saying that, they’re trying to kill the bill before it even gets started,” said Alison Reardon, legislative consultant for the Service Employees International Union, which represents thousands of immigrant workers. “We should continue to work to secure our borders, but there’s no way to do that and wait for legalization. Border security is an ongoing thing.”