Backers of a measure to limit affirmative action in Oklahoma say they have gathered enough petition signatures to put the referendum before the state’s voters in November 2008.

The Oklahoma Civil Rights Initiative — the state group behind the measure — has until the end of the day today to submit enough petition signatures to Oklahoma’s secretary of state to get its proposed amendment to the state Constitution on the ballot. W. Devin Resides, an Oklahoma City lawyer who is a leader of the effort, said this morning that he felt confident the group had obtained enough signatures to meet state requirements, and he planned to submit the documents this afternoon.

Campaigns are under way to get similar measures on the November 2008 ballot in four other states — Arizona, Missouri, Nebraska, and New Mexico — as part of what the group coordinating the effort, the American Civil Rights Coalition, is calling “Super Tuesday for Equal Rights.”

In contrast to their counterparts in the other four states, who generally have until spring or summer to gather signatures, those in Oklahoma had a much shorter deadline: 90 days from when state officials certified their proposed ballot language, in early September.

The group needed a minimum of about 138,900 signatures, the equivalent of 15 percent of the votes cast in the state’s last gubernatorial election. It initially hoped to gather more than 165,000 signatures, to ensure it would still have enough if some were invalidated. The group had difficulty reaching its goal because of the short deadline and a state law prohibiting it from hiring people from out of state to circulate petitions, but it nonetheless has gathered well over the minimum needed, Mr. Resides said. —Peter Schmidt