Forty years after the Rev. Martin Luther King Jr. was killed, we sometimes talk about race in America as if nothing has changed. The truth is that everything has changed -- mostly for the better -- and that if we're ever going to see King's dream fulfilled, first we have to acknowledge that this is not an America he would have recognized.

There remains a significant income gap between whites and blacks in this country, although it shrinks when educational level is factored in. But the gap in wealth, or net worth, is huge, even when you control for education, age, family size and whatever else you want to throw in. Still, African Americans control an estimated $800 billion in purchasing power. If that were translated into gross domestic product, a sovereign "Black America" would be the 15th- or 16th-richest nation on earth.

The African American poor are a smaller segment than they were 40 years ago, but arguably they are further from full participation in society than they were in King's era. It's not that they have no interest in climbing the ladder, it's that too many rungs are missing.

While some deride such moves as attempts to slough off responsibility or soothe the consciences of white liberals, James Campbell, who chaired the 2003-2006 Brown University effort to examine the school's ties to the slave trade, sees efforts to re-examine history as a step towards justice, not an end unto itself. "I believe that how we see the past matters," says Campbell, "because how we understand history helps shape the present matrix of political possibility."

To Cohen, who remembers attending segregated sports games in the South as a child, an apology for slavery and its legacy isn't about pointing fingers but coming to terms with a history that for too long has been elided.

"I didn't own slaves. My parents didn't own slaves," says U.S. Rep. Stephen Cohen. "But as a government for a century, we continued to perpetuate the racism that was at the root of slavery in this country," he says.

After a century of segregation and racial violence, he says, "This is an attempt to start the healing." 

It is true that some liberal scholars like me, having studied the text and history closely, have concluded, against our political instincts, that the Second Amendment protects more than a collective right to own and use guns in the service of state militias and national guard units. Opponents of the District’s flat ban on handgun possession have cited my words to the court and in newspaper editorials in their support.

But nothing I have discovered or written supports an absolute right to possess the weapons of one’s choice. The lower court’s decision in this case -- the D.C. Circuit Court of Appeals found the District’s ban on concealable handguns in a densely populated area to be unconstitutional -- went overboard. Under any plausible standard of review, a legislature’s choice to limit the citizenry to rifles, shotguns and other weapons less likely to augment urban violence need not, and should not, be viewed as an unconstitutional abridgment of the right of the people to keep or bear arms.

Obviously, the intrinsic rewards of learning aren't working in New York's schools, at least not for a lot of children. It may be that the current state of achievement is low enough that desperate measures are called for, and it's worth trying anything. And we don't know whether in this case, motives will complement or compete.

But it is plausible that when students get paid to go to class and show up for tests, they will be even less interested in the work than they would be if no incentives were present. If that happens, the incentive system will make the learning problem worse in the long run, even if it improves achievement in the short run -- unless we're prepared to follow these children through life, giving them a pat on the head, or an M&M or a check every time they learn something new.

Is there a compelling public interest in preventing loving, committed, same-sex couples from getting legally married? The clear answer is no. Ask Canada. Ask Spain. Ask South Africa. Ask Massachusetts!

The real compelling public interest is in ending bigotry and discrimination. It's being true to our nation's values of freedom, fairness, justice and equality. We cannot and should not be able to regulate what individuals think and believe. But when it comes to what the government does, it must treat everyone equally. This includes same-sex couples and their families.