American Scoundrel: love, war and politics in Civil War America, by Thomas Keneally

Dan Sickles was a rascal. He was, for a start, a persistent, unregenerate rat with women. It was not just that he was an unrepentant adulterer before, during and after two marriages. There was something repulsively cold about the way he treated women. Sent as a diplomat to the US embassy in London, he presented at Queen Victoria's court his mistress Fanny White, a notorious New York prostitute.

He was a creature of the political corrupters of Tammany Hall, and financially dishonest. As an old man, he simply helped himself to $28,000 of public funds: the equivalent of at least a cool million today. And he was an admitted, though unconvicted, murderer. He shot and killed his wife's lover in cold blood in Lafayette Square, in full view of the White House, and was then acquitted on a dodgy plea of temporary insanity.

He wasn't all bad, though – not from Thomas Keneally's point of view. He hated England, for a start. Keneally is best known as the author of the book on which the film Schindler's List was based. But he also wrote The Great Shame, about Thomas Francis Meagher and his Irish companions in rebellion at the time of the great potato famine, who were transported to Keneally's native Australia.

American Scoundrel is dedicated to the American Keneallys. They and their Australian kin will enjoy the book's relentless snide Anglophobia. For British readers, that will be a minor irritation in an excellent read. Our shoulders are broad.

For Dan Sickles was much more than a glib shit who got away with murder. He started out as printer, then made his way as a clever New York lawyer. He worked as a diplomat in London, then much later as ambassador in Madrid. He was an influential congressman in the stormy years just before the Civil War, a Democrat prepared to go a long way to keep the Southern slaveowners in the Union. One of the best parts of this book is Keneally's picture of Washington high society on the eve of the "irrepressible conflict".

After his acquittal for murder, Sickles was in disgrace. The Civil War came to his rescue. He raised a brigade of New Yorkers and rose to be a major-general in the Union army. His headquarters were said to be "a combination of bar-room and brothel".

Sickles was as cool under fire as on a capital charge. At Gettysburg, he had his leg shot off, though not before he had either won the battle or nearly lost it (according to which side you take) by pushing his division forward to the peach orchard on Cemetery Ridge, creating a kink in the blue line. He lived until 1914, when he was 97, idolised and detested.

It is a great tale, and Keneally has told it with skill and relish, with affection for wicked Dan Sickles, and even more for his wayward but affectionate wife, Teresa. My own sympathies were with his various victims, but Keneally is no doubt right in thinking that all the world loves a ruthless bastard.