FALL RIVER, Mass.—Four new members of the House were hanging out at a bar back at the end of 2012, after a long day of new-member orientation at Harvard’s Kennedy School: Joe Kennedy of Massachusetts, Beto O’Rourke of Texas, Tulsi Gabbard of Hawaii, and Eric Swalwell of California.A woman approached the table, and caught O’Rourke’s eye.“She’s like, ‘Are you who I think you are?’ And I thought, I just won this seat in Texas and she knows about me, and this is cool. I’m big-time,” O’Rourke told me last year, a few months before his Senate run took off.