Sometimes this is misspelled "tallyranding." It's not certain that Talleyrand ever said it; it was probably attributed by his many enemies.
WHY IT'S BAD
In March 1804, when Napoleon Bonaparte was consul of the French Republic, he became aware of the fact that a leader of the royalist opposition was hiding out across the border of France. Napoleon had him kidnapped, brought back to Strasbourg, "tried," and put to death. The unfortunate young man was never accused of doing anything illegal; he had not violated the laws of the French Republic because he was not in France, and when he had been, he was serving the previous government.
Whoever actually said "...worse than a crime...a blunder" was ignoring the fact that it was a crime to murder an innocent person, and focusing instead on the fact that it was DUMB. In some cases, such as this one, it's a reasonable thing to do; but if it becomes a habit then moral judgment is deliberately suspended.
It's the asshole's substitute for moral fiber.
(Taken from the comments of Jim Henley's blog, *Unqualified Offerings*, "I Already Shot You"--May 31, 2010)