The Spoleto USA chamber music festival is one of the nation’s best-loved summer institutions. But even a festival which continues to set records for attendance and ticket revenue is not immune from the ravages of the current American economic climate. Corporate sponsorships for Spoleto are down sharply this year, and while no one is talking about any major cuts just yet, the prospect of a return to massive debt and layoffs for the festival is certainly the proverbial elephant in the boardroom at the moment.