Alexandria Ocasio-Cortez has come a long way since 2018. When she first arrived on the political scene by beating out not just an incumbent, but a member of her party’s leadership in a Democratic primary contest, she was a rebel — an avatar of insurgent impulses within her coalition. And, among Republicans, something of a joke. Now, she’s the Democratic Party’s most popular elected official. A Yale University poll released this week found that among Democrats, Ocasio-Cortez boasts the single highest net favorability rating of all the party’s many potential 2028 presidential candidates — a sky-high 62%. In addition, 41%...