JPMorgan Chase CEO Jamie Dimon talked about a higher calling yesterday at the Yale CEO Summit, a two-day confab staged by Yale professor and author Jeffrey Sonnenfeld. “We all need to get more involved in politics and regulation,” Dimon told the audience of corporate chiefs, ex-CEOs, and lofty thinkers. “It’s almost against our nature, but we need to be engaged in the debate…Politics is frustrating, but we need to be there.” (Dimon, accepting the Summit’s “Legend in Leadership” award, scored big with his candor about the global turmoil — and I’ll share his remarks with you on Postcards next week.)

Meanwhile, Morgan Stanley CEO John Mack says he started noticing, even before the market meltdown, CEOs delving much more into public policy and D.C.-type doings. If the government doesn’t lead the charge to fix the environment, for instance, the onus falls on powerful chiefs like Lee Scott of Wal-Mart and A.G. Lafley of Procter & Gamble . The CEOs are, in essence, regulating their suppliers to be green.

And while these chiefs and other survivors reexamine their roles as leaders, many others, I see, are reevaluating their lives and careers. Power: Is it really worth the stress? On Tuesday, the day after Christie Hefner stunned everybody — even her colleagues at Playboy — by quitting her CEO post, I ran into her at lunch (at Michael’s, if you must know). Many suspect she has something new lined up. “Honestly I don’t,” she told me, adding that she wants to get more involved in public policy, education and board work. Women leaders, we agreed, tend to view their lives in chapters. Hef’s only daughter (lovely and polite, she always seemed to be the oddest CEO for Playboy) is now doing that.

Another former chief who has found a new calling: PepsiCo’s Steve Reinemund. Indra Nooyi’s predecessor is now dean of Wake Forest’s Calloway School of Business (named after the late Wayne Calloway, who was Pepsi’s onetime chief and Reinemund’s mentor). An ex-Marine with a religious bent, Reinemund always was seriously focused on values and ethics. Now he can flex those muscles on a new generation.

And one other CEO with a civic bent — Netflix founder Reed Hastings, once a Peace Corps volunteer and now a hardcore education reformer — wrote a Guest Post this week about CEO humility. For a poignant lesson about leadership, click here. And have a good weekend!