As the world honors Abraham Lincoln on the 200th anniversary of his birth, it’s worth recalling one of the less well-remembered moments of his career: his letter on January 19, 1863 to “the Workingmen of Manchester,” responding to their earlier address and resolutions in support of the North.

This was one of Lincoln’s earliest public letters, an art form he used to increasing effect throughout the remainder of the Civil War. The Manchester letter, though not as well known as his later letter on Clement Vallandigham, the ‘wily agitator’ and Copperhead, concerned the vital subject of British recognition of the Confederacy.

At a minimum, this would have heartened the South; at worst, it could have led to war between Britain and the North, and the defeat of the Union. Lincoln therefore treasured the support of the Manchester workers, hoping it would balance the intense suspicion of the free, liberal, capitalist North that prevailed among the British establishment.

It was, Lincoln pointed out, often claimed that

the attempt to overthrow this Government, which was built upon the foundation of human rights, and to substitute for it one . . . on the basis of human Slavery, was likely to obtain the favor of Europe.

But Lincoln rejected this claim. He refused to believe that the common people in Britain would accept the legitimacy of a power founded on slavery: to do so would be to refute all principles of “justice, humanity, and freedom.” And what Britain rejected, the rest of Europe would never accept.

Lincoln based his argument on his belief that a community of sentiment existed between the U.S. and Britain. He described them as “kindred,” and closed with his belief that the exchange of letters was an augury that “the peace and friendship which now exist between the two nations will be, as it shall be my desire to make them, perpetual.”

Lincoln was a visionary, in more ways that one. Relations between the U.S. and Britain after 1783 were rarely easy. Yet, as he so often was, Lincoln was generous and far-sighted in his faith in the coming Anglo-American reconciliation.

Of equal significance is Lincoln’s belief that national sovereignty, to be recognized by others, must rest on observance of basic standards. The anti-slavery movement was launched in Britain by Christian evangelicals. The Civil War, from their perspective and Lincoln’s, was a great test of the willingness of the civilized world to accept that any society that practiced slavery could not be accepted as a legitimate, sovereign state.

Today, that struggle has been so thoroughly won that – no matter what the ugly realities – no state today openly acknowledges that it condones slavery. What disfigures our world today is not what states say: it is what they do. We have forgotten Lincoln’s principle: that states which do not live up to basic values are not worthy of admittance into the community of nations.

There is room for much diversity in this community. But the recognition the world extends to North Korea, to Iran, to Zimbabwe, and to far too many others shows how far we are from upholding Lincoln’s vision. In an era when we have fulfilled his prescient faith in the Special Relationship, that failure – and its consequences – should be a constant reproach to Americans and Britons alike.