For most of its two decades overseeing the sprawling Virginia estate of James Madison, the fourth U.S. president, the Montpelier Foundation had either zero or just one African American member of its governing board, whose authorized strength is 25 members. That was astonishing because Montpelier, in addition to being Madison’s property, was also home to some 300 enslaved people over the course of more than a century who lived, worked in bondage and died there.

So it was a momentous if overdue step forward last year when the foundation announced it would share power equally, and achieve parity on its governing board of directors, with descendants of enslaved people. Those descendants were represented by a committee, recognized by the foundation, that included dozens of prominent African Americans in academics, business, finance and other fields. At last, Montpelier, a 2,650-acre historic site and museum northeast of Charlottesville that annually hosts tens of thousands of visitors, would have leadership that reflected its legacy. The foundation’s decision was hailed by cultural institutions across the country.

Now, that agreement, in letter and in spirit, has been shredded by the foundation’s White-dominated board. In an act of exceptionally bad faith, the board last month amended its bylaws so that it — and not the committee it had recognized as the legitimate stakeholder representing descendants of the enslaved — will decide which descendants are acceptable partners. To put it plainly, it is principally White people who will determine which Black people may join Montpelier’s governing clique, and which may not.

Despite its smokescreen of obfuscation — the foundation says it will continue to work with the descendants committee and seek parity — make no mistake: The board has reneged on its deal. When the descendants committee last month submitted a list of 40 African American candidates, of whom 10 might assume seats on the board in order to achieve parity with White members, the board refused even to consider the names. It did so despite having committed last year to accept new board members endorsed by the descendants committee.

The board’s move has been widely condemned, not least by Montpelier’s own employees and by the National Trust for Historic Preservation, which owns the estate but appears powerless to intervene owing to a 75-year concession agreement with the foundation.

Montpelier has a problem. It has gone from being a model for other such sites nationwide to being an embarrassment.