THE MOST IMPORTANT DEVELOPMENT in the immigration reform debate occurred not in the Senate’s debate on immigration, but rather in the Senate’s debate on prescription drugs.

The back-and-forth on immigration overshadowed the passage of the first major deadline in the new Medicare prescription drug benefit program. But the coincidence of these two political events could not be better timed: The government’s response to pressure for relaxing of the drug program’s deadlines today might foreshadow the government’s commitment tomorrow to immigration deadlines and standards.