A bipartisan group of 75 former US attorneys is calling on Attorney General Jeff Sessions to halt the separation of families on the US-Mexico border, writing that separating children from their parents “ultimately render[s] us less safe as a nation.”

“Like a majority of Americans, we are appalled that your Zero Tolerance policy has resulted in the unnecessary trauma and suffering of innocent children,” the group wrote. “But as former United States Attorneys, we also emphasize that the Zero Tolerance policy is a radical departure from previous Justice Department policy, and that it is dangerous, expensive, and inconsistent with the values of the institution in which we served.”

The letter went on:

Collectively, as former United States Attorneys, we have prosecuted tens of thousands of cases involving far more serious crimes than misdemeanor illegal entry offenses. And even in those far more serious cases, decisions involving the separation of children from their parents were made with extraordinary caution, and only after an evaluation of the specific circumstances of a particular case. Today, by contrast, your Zero Tolerance policy has produced a tragic and unsustainable result, without taking into account each family’s specific circumstances.

A growing number of citizens, public figures, members of Congress, former and current first ladies, and 600 members of the United Methodist Church — which counts Sessions as a member — have condemned the Trump administration’s policy.

In just six weeks, about 2,000 migrant children were separated from their families at the border and placed in government custody. These figures reflect only those children taken from the middle of May to the end of June, leaving open to question how many families have been separated in the following weeks.

Family separation is a consequence of prosecuting every case of illegal entry

The former US attorneys are criticizing the policy that’s at the root of the family separations at the border: the Trump administration’s decision that all adults crossing into the US illegally should be criminally prosecuted.

As Vox’s Dara Lind explained:

To be clear, there is no official Trump policy stating that every family entering the US without papers has to be separated. What there is is a policy that all adults caught crossing into the US illegally are supposed to be criminally prosecuted — and when that happens to a parent, separation is inevitable. Typically, people apprehended crossing into the US are held in immigration detention and sent before an immigration judge to see if they will be deported as unauthorized immigrants. But migrants who’ve been referred for criminal prosecution get sent to a federal jail and brought before a federal judge a few weeks later to see if they’ll get prison time. That’s where the separation happens — because you can’t be kept with your children in federal jail.

This is the policy the attorneys general are criticizing, arguing that it’s not only inhumane but also a poor use of federal resources. Time spent prosecuting illegal entry in federal court, they argue, is time that can’t be spent on other, more serious crimes, including “a terrorist plot, a child human trafficking organization, an international drug cartel or a corrupt public official firearms cases, violent crime cases, financial fraud cases, and cases involving public safety on Indian reservations.”