Strategy on Rivals Career Holds Pitfalls for President

Last week, a few dozen hedge fund and investment executives arrived at the Park Avenue home of Hamilton E. James, president of the private equity firm Blackstone. Each had paid $35,800 to spend two hours at a fund-raiser with President Obama, but the timing proved awkward: A few hours earlier, Mr. Obamas campaign had begun a blistering attack on Mitt Romneys career in private equity, the same business in which Mr. James has earned his many millions.

“Campaigns do what campaigns have to do, Mr. James later told friends. But...