During his five-year overhaul of the Nixon Presidential Library and Museum, Cold War historian Timothy Naftali won wide praise for transforming a much-ridiculed institution into a house of serious scholarship under the auspices of the National Archives and Records Administration.

Yet nobody was surprised that the private Richard Nixon Foundation — run by fierce loyalists of the former president — didn't honor Naftali when he left as director last month to join a think tank and write a book. The raw, unflinching Watergate exhibit he unveiled in March was, in the loyalists' view, deeply unkind to Nixon's legacy.

The foundation, which had run the library with private funds from its inception in 1990, had a chilly relationship with Naftali since he was appointed director in 2006 with the clear orders to make over an institution that seemed designed only to burnish Nixon's image.

Now, a fuller portrait is emerging of the campaign the loyalists waged and the tactics they employed — including the use of high-level political pressure — to thwart Naftali's efforts at the library....