On an Election Day when activists of many ideological stripes could tout victories on ballot measures, the narrow passage of a pro-stem cell research initiative in Missouri sent a mixed message about that issue’s political potency.

Supporters of the amendment to Missouri’s constitution called its passage a “mandate for protecting stem cell cures.” Yet the measure, which prohibits the state from banning any embryonic stem cell research permitted under federal law, passed by just 55,000 votes out of more than 2 million cast – a sharp drop from polls last year that showed the proposal drawing nearly 70 percent approval.

Democratic gains nationwide brought defeat for conservatives on numerous other state referendums, but not all. Voters in Arizona made their state the first to defeat a same-sex marriage ban on the ballot, though seven other states approved such bans.

Increases to the minimum wage passed in all six states where voters considered the issue, echoing a major priority of the incoming Democratic congressional leadership. In addition, six states rejected proposals to cut taxes or limit government spending.

Missouri’s stem cell initiative spawned the most expensive and in many ways the most intense battle over a ballot measure. Officials with the Missouri Coalition for Lifesaving Cures, which led the fight for the constitutional amendment, expressed relief that it would forestall future attempts to outlaw embryonic stem cell research.

“Our great medical institutions and universities can now continue to attract the best minds, and all of our state will benefit from that,” said Donn Rubin, chairman of the pro-stem cell research group.

Despite a pro-initiative campaign that enlisted celebrities such as actor Michael J. Fox, opponents of embryonic stem cell research made strides in the last few weeks. To counter Fox’s television ad, which made reference to his fight against Parkinson’s disease, anti-initiative forces brought out celebrities such as St. Louis Cardinals pitcher Jeff Suppan and “The Passion of the Christ” star Jim Caviezel.