The banners were rainbow, but the politics were blue. Obama campaigners spent the weekend outdoors at more than a dozen major gay-pride events held in cities nationwide. The president’s reelection efforts hope to tap the pool of gay voters who typically support Democrats 3 to 1 over Republicans and who seem more likely than ever to tilt for Obama this year after he announced his personal support for same-sex marriage. “It’s like shooting fish in a barrel this year,” said Democratic consultant Steve Elmendorf. “I think people are just tremendously grateful.” Three hundred Obama campaigners marched in Chicago’s gay-pride parade Sunday.