A president's regret isn't a tidy little footnote; it's a crack in the foundation. From the books I've read, that kind of personal turmoil bleeds into everything. He might start overcompensating, trying to control the pack with an iron fist because he fears another lapse in judgment, which just breeds resentment. Or, he could swing the other way and become indecisive, second-guessing every command because he's terrified of making another mistake that hurts someone.
I remember a scene in one shifter romance where the Alpha, after failing to protect his mate in the past, became so paranoid about external threats that he isolated the whole pack, stifling their lives. His regret didn't make him wiser; it made him fearful, and a fearful leader is a vulnerable one. The best arc I've seen is when the regret forces a brutal self-audit, making him delegate, trust his beta, and actually listen—transforming pain into a different kind of strength, not brute force but strategic humility.