Sen. Chuck Schumer tells Talking Points Memo that there are three big hurdles to immigration reform:

“First, defining metrics that demonstrate the border is secure,” he told reporters on Thursday. “Second, defining exactly what the path to citizenship looks like and how it proceeds. [Third,] reaching an agreement between business and labor on a future flow program.”

Local Arizona politicians could have a big role in the Senate's framework for immigration reform—which could mean a big stall over the question of whether the border is secure enough before resolving the status of undocumented immigrants now in the U.S.:

The Senate’s plan also calls for a commission of Southwestern governors and other state officials to oversee the process. Members of the Senate group backing the idea say the ultimate decision on the trigger would be left to the Department of Homeland Security and that it’s unconstitutional to give the commission a veto, but conservatives could still press to expand their role in a final deal or give Congress a greater say in determining whether the border is secure. And then there’s the metrics used to define a secure border. Democrats want an easily measurable checklist, like number of agents deployed or whether or not they have enough drones in the air. But the vaguer the definition, the better chance immigration reform opponents have of slowing down the naturalization process in the future.