John McCain asked former campaign staffers Friday to avoid engaging in a back-and-forth over claims made by former running mate Sarah Palin in her new book, CNN has confirmed.

On a conference call with senior campaign advisers, the former Republican presidential candidate asked them to hold back from responding – telling them, in effect, that "this too shall pass," according to sources familiar with the call.

On Friday, McCain conceded to the reality of the media firestorm surrounding Palin's charges against his team, and told them he understood if they felt the need to defend themselves. But the Arizona senator called for a minimalist approach, suggesting that his former aides avoid television appearances.