Half a world away from her birthplace in Ethiopia, teenager Hana Williams died on a rainy night in the backyard of what a prosecutor called a “house of horrors” — the rural home of her adoptive family in Washington state.

The official causes of her death in May 2011 were malnutrition and hypothermia. She had been forced outside as a punishment. Authorities said that, during three years of adoption, Hana had been beaten repeatedly with switches, starved and made to sleep in a locked closet.

The parents, Larry and Carri Williams, have been convicted of manslaughter and face sentencing Oct. 29.

Yet more than two years after Hana’s death, few meaningful steps have been taken by state policymakers to reduce the chances of other adopted children suffering such abuse. A task force offered detailed recommendations, and a limited bill was introduced in Washington’s legislature. But it died in committee this year because of concerns it might infringe on parental rights.

“We really are struggling to find something that will be both effective and constitutional,” said the bill’s sponsor, Rep. Mary Helen Roberts, a Democrat from Snohomish County. She plans to continue her efforts.

While most adoptions are successful, the Williams case is among several recent grim adoption developments around the United States, prompting urgent calls for better safeguards and more post-adoption support. Yet many of those making the appeals admit to frustration; they say they have sounded alarms before, and they hold out little hope for prompt, sweeping responses that would strengthen international and domestic adoptions nationwide.

A key reason is the nature of adoption in the United States — marked by inconsistent laws, incomplete data and the absence of any central authority. There are no authoritative statistics on the number of adoptions that fail and no reliable source of federal funding for post-adoption services. And there is a multitude of passionate organizations with often diverging views on how to maximize success stories and minimize tragedies.

“There are so many different perspectives — the rights of the child, the rights of the family, the rights of the states,” said Sharon Osborne, president of the Children’s Home Society of Washington, who would like to see some form of post-adoption assessments in her state.

“What we are advocating for is the best possible situation for a child and his or her newly formed family,” she said. “We can’t seem to get through the political challenges to make it a reality.”

A report compiled after Hana Williams’s death documented 14 other cases of severe abuse or neglect of adopted children in the state from 2009 to 2011. Other cases of adoptions gone wrong have been highlighted by Russia, which last year banned adoptions of Russian children by Americans. Though the move was part of a broader political skirmish, it afforded Moscow the opportunity to complain about mistreatment and lack of post-adoption oversight. About 20 Russian adoptees have died at the hands of their American parents. In 2010, a Tennessee woman, having lost patience with her 7-year-old adopted son’s behavior, sent him back to Moscow on a plane — alone.

More recently, articles by the Reuters news agency in September detailed a phenomenon known as “re-homing,” in which adoptive parents who have grown frustrated with a child — often one adopted from abroad — arrange through Web sites for another family to take the child.

The sites were not regulated by any government authority, and the families taking the adopted children were not subject to any screening. In some cases, mistreatment ensued. Advocacy groups are now calling for such child-swapping to be outlawed or subject to oversight by state child-protection workers.

“It makes you wonder: Is anyone going to want to do adoptions with us?” said Susan Jacobs, the State Department’s special adviser on children’s issues and the Obama administration’s point person on international adoptions.

Some adoption advocates worry that the negative developments will result in fewer adoptions — and thus consign more children to lives in foster care or foreign orphanages.

Some improvements are expected next July, when higher standards take effect for all U.S. adoption agencies that handle international adoptions. Among the many provisions of the Universal Accreditation Act is one requiring parents to receive training before the adoption to prepare them for future challenges.

The law does not specifically address post-adoption problems. Children adopted from abroad generally become U.S. citizens without delay, and thus it would be problematic to conduct any special tracking of them unless it was on a voluntary basis.

Although the State Department doesn’t have direct responsibility for international adoptions once they’re completed, Jacobs expressed interest in working with others in the adoption field to improve support services.

“We need to help parents to find resources when they are having trouble . . . so they don’t turn to the Internet to get rid of their kids,” she said.

During the pre-adoption process, Jacobs said, parents should be given accurate information about a child’s medical and psychological condition to minimize the chances of frustration later on.

Under State Department policies, U.S. agencies that arrange international adoptions are subject to accreditation by the independent Council on Accreditation. Its president, Richard Klarberg, wants to tighten the standards for how the agencies screen and educate parents, notably in cases involving children with special needs.

“Our goal is to force or cajole the providers to demonstrate they are providing very intense training and preparation,” he said. But he acknowledged that screening is challenging.

So is post-adoption monitoring. Melanie Chung-Sherman, an adoption therapist in Dallas who was adopted from South Korea, said such monitoring would be unfeasible unless parents volunteered for it. However, Chung-Sherman said families considering adoption should be made aware of the potential challenges.

Blunt pre-adoption conversations can be crucial because many of the children being adopted out of foster care and from abroad are psychologically troubled. Mental health services for adoptive families are widely viewed as inadequate — too little funding and too few professionals trained in adoption-related trauma.

Among the organizations trying to fill the void is the Center for Adoption Support and Education in Burtonsville, Md.

“I see many well-meaning, loving, educated parents who come in at their wit’s end,” said the center’s chief executive, therapist Debbie Riley. “They’re left on their own to fend for themselves.”

By and large, advocates’ long-standing recommendations — among them a call for federal funding for post-adoption services — haven’t translated into policy. There are some new proposals in Congress aimed at providing more funding for post-adoption services, but prospects for passage are uncertain.

— Associated Press