The morning’s news of the death of Tom Lantos — Democrat of California and the only Holocaust survivor ever to serve in Congress — arrived as an angry slap even as we knew it was imminent. The 80-year-old was diagnosed with cancer of the esophagus last December, and had faded from public view since then. On the second day of 2008 he announced he would retire at the end of the year. It would have marked his 28th in Congress.

While the appreciations this morning (this one included) are all leading with mention of the Hungarian-born lawmaker’s unique and brutal experience in Hitler’s Europe, it was how he used that suffering to steer his politics that will solidify his legacy. A co-founder of the Congressional Human Rights Caucus, Lantos was a fiery defender of Democracy and human rights across the globe. Apartheid in South Africa; genocide in the Balkans; Internet policing in China; the encroachment of citizens’ rights here at home under the PATRIOT Act: No abuse seemed too small; no country was too obscure.

In 2005, two years before it was fashionable, he led a march in front of the Burmese embassy in Washington to protest the house arrest of Nobel Prize winner Aung San Suu Kyi. A year later he himself was arrested in front of the Sudanese embassy for protesting the ongoing genocide in Darfur. The list goes on.

Lantos was also an ardent defender of Israel, but he was not always on the side of the angels. In 2002, as a supporter of the White House push to war with Iraq, he helped Republicans pass legislation authorizing our forces against Saddam Hussein. After the vote, Lantos said, “The train is now on its way,” according to a New York Times report at the time.

Still, after his initial support, Lantos changed his tune on the war, emerging as one of the most vocal critics of last summer’s surge. Democrats now are left with the unenviable task of replacing what is irreplaceable.

In announcing his retirement last month, the House Foreign Affairs Committee chairman characterized his service to his adopted country this way:

“It is only in the United States,” he said, “that a penniless survivor of the Holocaust and a fighter in the anti-Nazi underground could have received an education, raised a family, and had the privilege of serving the last three decades of his life as a member of Congress. I will never be able to express fully my profoundly felt gratitude to this great country.”

The biographers can begin with that, but the larger story here is overseas.