The July 1 editorial “The torture of solitude” rightly called for reform of the cruel, profoundly damaging and expensive practice of solitary confinement.

A good place to start would be in the federal prison system, the nation’s largest. At a Senate hearing last month, Federal Bureau of Prisons Director Charles Samuels Jr. admitted that his agency houses 7 percent of its prisoners in solitary on any given day. That rate is far higher than those of most state systems and amounts to a staggering 15,000 people. Although the bureau declines to provide comprehensive data, we know that some federal prisoners have been held in continuous solitary confinement for more than a decade.

From Maine and Mississippi to Illinois and Colorado, state-run prisons have successfully reduced their use of solitary confinement, saving millions of dollars in the process. Yet the bureau remains content with business as usual in the federal system.

Congress should not accept the status quo. It should require greater transparency from the prisons bureau in its use of solitary confinement and insist that it implement the kind of reforms that have succeeded at the state level.

David Fathi, Washington

The writer is director of the American Civil Liberties Union’s National Prison Project.