They have a strong constitution. When Irish voters registered a resounding “yes” for gay marriage last May, many thought legalizing abortion would be next. But changing social mores may not have shifted the historically Catholic country from its staunch pro-life position. While 81 percent of the nation supports widening access to abortion, which currently can land women in prison, pro-choice advocates haven’t gained much legal ground. Now many groups are calling for a referendum to repeal their constitution’s ban — but political scientists say change is far from assured.