The former president of the United States agreed to accept a lifetime achievement award at the June 2014 event after Ms. Nemcova offered a $500,000 contribution to the Bill, Hillary and Chelsea Clinton Foundation. The donation, made late last year after the foundation sent the charity an invoice, amounted to almost a quarter of the evening’s net proceeds — enough to build 10 preschools in Indonesia.

Happy Hearts’ former executive director believes the transaction was a “quid pro quo,” which rerouted donations intended for a small charity with the concrete mission of rebuilding schools after natural disasters to a large foundation with a broader agenda and a budget 100 times bigger.

“The Clinton Foundation had rejected the Happy Hearts Fund invitation more than once, until there was a thinly veiled solicitation and then the offer of an honorarium,” said the former executive director, Sue Veres Royal, who held that position at the time of the gala and was dismissed a few weeks later amid conflicts over the gala and other issues.