WEST DES MOINES, IOWA — Kansas Sen. Sam Brownback, among the most conservative of the potential Republican presidential candidates, said Tuesday there’s room in the GOP for candidates who favor gay rights, but he warned that such politicians wouldn’t be welcomed by the party’s conservative base. “It’s a big-tent party and has been for a long period of time, particularly since Ronald Reagan talked about this being a party of different viewpoints,” said Brownback. “If somebody agrees with you 80 percent of the time, he’s not your enemy.” Brownback, in the midst of another visit to Iowa, was asked about...