Tim Ryan, a former 20-year congressman, is making more money now than he ever did in his life — including $246,943 to advocate for natural gas last year — but won’t dismiss a return to politics.

It was a moment as surreal as it feels long ago. Rep. Tim Ryan of Ohio and Rep. Tulsi Gabbard of Hawaii, would-be populists both as well as combatants for the presidency, got into it. Long before ...