I'm almost done with Peter Hart's Mick: The Real Michael Collins, and though the book has some commendable aspects to it, it also has a certain quality that keeps rubbing me the wrong way. Louis Menand's critique of the biography genre seem to perhaps overstate the case, but at least nail the problem with Hart's book:
[T]he premise of biographies is that the private can account for the public, that the subject’s accomplishments map onto his or her psychic history, and this premise is the justification for digging up the traumatic, the indefensible, and the shameful and getting it all into print. How centrally that kind of information figures in the biographical account depends on the tact and ingenuity of the biographer, but a biography that did not use events in its subject’s personal life to explain his or her renown is almost unimaginable. Still, the premise poses a few problems.
For one thing, it leads biographers to invert the normal rules of evidence, on the Rosebud assumption that the real truth about a person involves the thing that is least known to others. A letter discovered in a trunk, or an entry in a personal notebook, trumps the public testimony of a hundred friends and colleagues. Biographers go into a professional swoon over stories that some famous person has made a bonfire of a portion of his or her correspondence, or that notebooks in an archive are embargoed until the year 2050. That stuff must explain everything! Why should we especially credit a remark made in a diary or a personal letter, though? The penalty for exaggeration and deception in those forms is virtually nonexistent. People lie in letters all the time, and they use diaries to moan and to vent. These are rarely sites for balanced and considered reflection. They are sites for gossip, flattery, and self-deception. But diaries and letters are the materials with which biographies are built, generally in the belief that the “real” person is the private person, and the public person is mostly a performance.
As Brendan Nyhan says this seems in many ways to parallel some of the pathologies of political journalism. John Edwards' anti-poverty program should be dismissed because he has a big house. Collins was "really" driven by personal ambition rather than Irish nationalism as can be seen in his 1916 correspondence about the possibility of moving to Chicago.