Once in office, Lincoln was endlessly faulted by abolitionists. He held off issuing the Emancipation Proclamation until the Civil War was nearly two years old -- and his directive had little effect, since it liberated slaves only in Confederate states, which did not recognize his authority.
The slave states that remained in the Union were exempt. As for letting blacks vote, he didn't get around to a tentative endorsement until after the Confederate surrender.
Yet in the end, we know, it took Lincoln to abolish slavery and set the nation on the path toward racial equality. He is not remembered as the Great Emancipator for nothing.
Like him, Obama has to deal with hard political realities. Had he endorsed same-sex marriage four years ago, the White House would be occupied by John McCain, who supported the military's ban on gays. Were Obama to launch an all-out campaign for a federal law, he would pave the way for GOP victory that would set back the cause of gay rights.
He has done what he can, and more than any of his predecessors. There is something to be said for a president who, after much delay, takes even a mild stand in favor of same-sex marriage -- and nudges the nation toward greater freedom and equality.
The former slave and black leader Frederick Douglass might have understood. What he said of Lincoln's approach to slavery could also be said of Obama on same-sex marriage: "Viewed from the genuine abolition ground, Mr. Lincoln seemed tardy, cold, dull, and indifferent. But measuring him by the sentiment of his country, a sentiment he was bound as a statesman to consult, he was swift, zealous, radical, and determined."
Today, the critics get their say. Years from now, it's what Obama did that will be remembered.