DUBLIN – Ireland has voted resoundingly to legalize gay marriage in the world’s first national vote on the issue, leaders on both sides of the Irish referendum declared Saturday even as official ballot counting continued. Senior figures from the “no” campaign, who sought to prevent Ireland’s constitution from being amended to permit same-sex marriages, say the only question is how large the “yes” side’s margin of victory will be from Friday’s vote. “We’re the first country in the world to enshrine marriage equality in our constitution and do so by popular mandate.