The death of Rosa Parks, the civil rights heroine who in 1955 refused to give up her seat on a bus to a white man and sparked the Montgomery, Ala., bus boycott, is an occasion to remember that segregation is still with us today in New York, primarily in our government-run schools. Fifty years after Rosa Parks made her stand, some reports reckon that New York’s schools are the most segregated in the nation.

We were reminded of this by a letter in the Sunday New York Times Book Review by Jonathan Kozol, the author of the book “The Shame of the Nation.” “New York has the infamy today of being the most segregated and unequal state for black and Hispanic students in the nation,” Mr. Kozol wrote, referring to “conditions of near-absolute apartheid” that “now prevail in New York City’s schools.”

A 2003 report by the Civil Rights Project at Harvard University found that New York was the “most segregated state” for black students, meaning a black child in New York was less likely to be exposed to white classmates than is a black student in Alabama or Mississippi or any other state in America. The same study found New York is the “most segregated state” for Latino students and that only 15.3% of students in the city’s public schools are non-Hispanic whites, significantly below the percentage of non-Hispanic whites in the school-age population in the city, which the census puts at about 23%.

When one regards individual schools rather than the state or the city as a whole, segregation is even more marked. The Web site of the city’s education department reports that at Crotona Park West Community School in the Bronx, only 0.2% of the student population were non-Hispanic whites in 2002-03. There are entire classes with no white students. Andrew Beveridge, a professor at Queens College, reported in the Gotham Gazette earlier this year on federal data showing that the student population at the city’s private high schools is 66% non-Hispanic whites and at Catholic high schools is 48% non-Hispanic whites.

Defenders of the status quo argue that contrary to the situation in the segregated South in Rosa Parks’s day, New York has no laws banning white students from public schools or black students from private schools. But public policy – such as the hostility to vouchers that would allow poor students to enter private schools – brings about a result similar to what de jure racial segregation did. What other way to describe a system in which the private schools are 66% non-Hispanic white and the public schools are 15% non-Hispanic white?

New York City now faces a court order to add about $5 billion a year to the $20 billion or so that the city already spends on its public schools. Divided among about 1.1 million students, the money could be turned into a voucher worth about $23,000 a year – enough for tuition and fees at the city’s finest private schools and enough to fund the creation of fine new private schools. Vouchers may be caricatured as a conservative fantasy, but the idea has won the support of Democrats such as the mayor of Washington, D.C., Anthony Williams, and a former Democratic congressman from Queens, the Rev. Floyd Flake. It is the way to begin the integration of New York schools and extend to the city the dream that Rosa Parks began 50 years ago.