The heroic whistleblower and peace activist Daniel Ellsberg is dying.

In an open letter to his friends and supporters, Ellsberg announced that two weeks ago he learned that he has inoperable pancreatic cancer with a prognosis of three to six months. The letter is beautiful and inspiring, but it's also as heart-rending as anything you'll ever read, largely because within it Ellsberg makes it abundantly clear that he has extremely urgent concerns about the world he will soon be leaving behind.

"As I write, 'modernization' of nuclear weapons is ongoing in all nine states that possess them (the US most of all)," Ellsberg writes. "Russia is making monstrous threats to initiate nuclear war to maintain its control over Crimea and the Donbas – like the dozens of equally illegitimate first-use threats that the US government has made in the past to maintain its military presence in South Korea, Taiwan, South Vietnam, and (with the complicity of every member state then in NATO ) West Berlin. The current risk of nuclear war, over Ukraine, is as great as the world has ever seen."

Ellsberg writes of the "scientific near-consensus" that a nuclear war between the US and Russia would cause a nuclear winter that ends most life on earth, and mourns the fact that this understanding has had no bearing on the behavior of the world's major nuclear powers.