A Maryland law that would give in-state tuition breaks to illegal immigrant students at public colleges seems headed to voters as a referendum after a successful petition drive by its opponents.

Maryland’s version of the DREAM Act would have assured lower resident tuition rates for illegal immigrants at state universities. The cumulative savings — or costs, depending on one’s perspective — amount to an estimated $40,000 per student in a four-year program.

Opponents of the law today reached the necessary 100,000 signatures to throw the measure back to voters as a referendum in November 2012, according to my colleague Aaron C. Davis. The law would have taken effect this month.

Maryland’s law ran counter to a national trend. At least three states — Arizona, Colorado and Georgia — have moved to deny in-state tuition to illegal immigrants since 2006. At least 10 states, including California and Texas, have laws that grant in-state tuition to illegal immigrants, but several repeal efforts are underway.