Arnold & Porter’s class action against the Bureau of Prisons comes as other Am Law 200 firms are mounting constitutional challenges to solitary confinement practices and substandard prison health care across the country. These are three of the most prominent:

Firm: Nelson Mullins Riley & Scarborough

Defendant: South Carolina Department of Corrections

After more than a decade of work on behalf of mentally ill prisoners in the South Carolina state prison system, Nelson Mullins won a ruling in January 2014 from South Carolina Circuit Judge Michael Baxley. Calling the case the most troubling he’d seen in 14 years on the bench, Baxley found the state’s treatment of mentally ill inmates, which included a disproportionate use of solitary confinement, violated the Eighth Amendment’s ban on cruel and unusual punishment. Nelson Mullins continues to represent the prisoners in mediation with state officials. Throughout the effort, which included a five-week bench trial in 2012, Nelson Mullins has logged about 45,000 pro bono hours, including nearly 700 hours in 2013.

Firms: Jones Day and Perkins Coie

Defendant: The Arizona Department of Corrections

The two firms joined with the National Prison Project of the American Civil Liberties Union and the Prison Law Office in Berkeley in 2012 to mount a constitutional challenge to health care and isolation conditions in Arizona state prisons. Having beaten back a government motion to dismiss in 2012, the plaintiffs succeeded in getting U.S. District Judge Neil Wake in Phoenix to certify a class of roughly 33,000 inmates in March 2013. The U.S. Court of Appeals for the Ninth Circuit upheld Wake’s class certification decision in June. Last year alone Jones Day dedicated 2,315 hours to the case, while Perkins Coie donated 5,179 hours.

Firm: Weil, Gotshal & Manges

Defendant: California Department of Corrections and Rehabilitation

Weil lawyers are representing a proposed class of inmates who have been held for more than a decade in solitary confinement in the Security Housing Units at Pelican Bay Prison (pictured, above and at left) along the northern coast of California. The firm, which dedicated more than 1,300 hours to the case last year, joined the effort at the request of the Center for Constitutional Rights. CCR filed suit in May 2012, claiming that long-term captivity in solitary confinement was a violation of the Eighth Amendment, and the lack of meaningful review for alleged gang members placed in solitary was a violation of their due process rights. U.S. District Judge Claudia Wilken in Oakland denied the state’s motion to dismiss in April 2013 and granted class certification in June.

In addition, the roster of firms working on these issues continues to expand. Covington & Burling, for instance, signed on in January to help the ACLU and the Southern Poverty Law Center challenge conditions at the East Mississippi Correctional Facility. Among other things, the suit alleges that the facility fails to provide sufficient treatment to inmates with serious mental illnesses and often places them in long-term solitary confinement. Covington donated more than 650 hours to the case in the first half of the year.