Bradley Manning is among the most polarising of all whistle-blowers. That the former US soldier is a criminal there is no doubt, but his theft of more than 700,000 classified documents on the Iraq and Afghanistan conflicts and his passing of them to the website WikiLeaks also makes him to some a hero, to others an enemy of the state. Consequently, the 35-year prison sentence he has been given by a military court on charges including theft and computer fraud is viewed as either too harsh or overly lenient. For his cause - to seek the truth - there has to be sympathy, although no matter how justified a belief is, if lawbreaking is involved there also has to be a cost.

The question, then, is whether Manning deserved the harshest sentence ever handed down by a US judge for leaking government secrets. That he was the biggest-ever offender in terms of the scale of his crime there is no doubt. Prosecutors argued he put lives at risk and chilled diplomatic relations with US allies. But there was also worth in much of what he revealed, military wrongdoing and incompetence uppermost. Among the disclosures was a video of a helicopter gunning down unarmed civilians, including children and journalists, in Iraq.

Previous sentences for military whistle-blowers are dwarfed by that given to Manning. Documents he revealed would have been declassified after 25 years; his jail term is a decade longer. With Edward Snowden continuing to release National Security Agency secrets in an arguably more damaging case, deterrence is obviously in the US military's mind. But with 92 million documents being classified each year and four million Americans having security clearance, similar incidents are inevitable.