California and New York — where almost 1 in 5 Americans live — are on their way to raising their minimum wage to $15 an hour, and the activists who spearheaded those efforts are now setting their sights on other similarly liberal, Democratic-led states. Illinois, Massachusetts, Michigan, New Jersey, Oregon, Rhode Island, Vermont and Washington are among the states with active “Fight for $15” efforts, and even economic experts who oppose the increased rate see it gaining momentum. “There is lots of pressure to do this,” said Douglas Holtz-Eakin, a former Congressional Budget Office director who is now president of...