Sheriff Joe Arpaio of Maricopa County, Arizona, whose trial in a class-action civil-rights lawsuit continues this week in Phoenix, didn’t get to be America’s most notorious anti-immigrant lawman by being shy. The camera and microphone are blood and oxygen to him. Where he goes, he trails TV crews, a gallery of rabid followers, posse volunteers and, every four years, supplicating Republican presidential candidates. The tent-city jail he calls his “concentration camp” is meant to signify brash, unchallenged power. In the blistering landscape of Phoenix, he blots out the sun.