One moment in the third Republican presidential debate encapsulates everything terrible about baby boomers and the way they’ve pillaged the U.S. economy. It came from Sen. Marco Rubio of Florida, a Generation Xer, who offered the standard line — you can hear it from the mouth of almost any American politician today — on how to keep Medicare and Social Security solvent. Rubio defended the idea that future workers will need to retire later or receive fewer benefits from those safety-net programs than current retirees. “Everyone up here tonight that’s talking about reforms,” he stipulated, was “talking about reforms for future generations. Nothing has to change for current beneficiaries.”That’s smart politics: The biggest generational voting bloc by far in the upcoming election will be baby boomers, a group that is just starting to draw its first Medicare and Social Security benefits — and does not want anyone messing with those benefits, thank you very much.It’s also bad economics.