From the start, the case of Adoptive Couple v. Baby Girl was a heart-wrenching one. On one side was the adoptive couple, Matt and Melanie Capobianco and the Hispanic birth mother, Christy Maldonado, who had selected the Capobiancos to raise her child. On the other was the birth father, Dusten Brown, who had alerted a pregnant Ms. Maldonado by text message that he wanted nothing to do with the baby on the way, but later embraced fatherhood and sought to block the adoption under the Indian Child Welfare Act on grounds that he is 3/128ths Cherokee.

In the middle was a bright, vivacious toddler named Veronica. She’s now nearly 4 years old.

The Capobiancos had raised Veronica since birth and, at 27 months, she was thriving. But the South Carolina family court concluded that, under ICWA, Veronica’s best interests were irrelevant. The court ruled it had no choice but to deny the adoption and grant custody to Mr. Brown, who at that point had never met the child.

In June of this year, the United States Supreme Court ruled that the South Carolina courts had made a terrible mistake. It agreed with the Capobiancos that Mr. Brown could not use the ICWA to block the adoption. It reasoned that the adoption did not cause the “breakup” of an Indian family, because Mr. Brown had never had any custodial rights over Veronica, because of his actions (and inactions) during Ms. Maldonado’s pregnancy and the months after Veronica’s birth.

Recognizing that the well-being of a young girl is at stake, the South Carolina Supreme Court swiftly ordered the family court to finalize the Capobiancos’ adoption of Veronica. And recognizing that Veronica undoubtedly has bonded with Mr. Brown in the 18 months since he erroneously was awarded custody (and surely mindful of the horrifyingly traumatic manner in which Veronica was ripped from their home and lives), the Capobiancos have offered regular visitations and a transition plan for Veronica’s custody that the South Carolina court described as “thoughtful” and, indeed, “generous.”

The nature of this case was that it could not have a happy ending, but the Capobiancos laudably were attempting to minimize the pain. It even seemed possible that Veronica could have healthy and enduring relationships with all the people who love her and have fought for her these last two years.

But since the South Carolina Supreme Court ordered Veronica’s adoption, things have taken a decidedly dark turn. After the South Carolina court ordered Mr. Brown or his “proxy” to return Veronica to the Capobiancos, no one showed up, Mr. Brown and the Cherokee Nation vowed not to comply, and members of Mr. Brown’s family promised that Veronica would not be handed over voluntarily. The situation reached a fever pitch last Friday, when South Carolina authorities were forced to issue a felony warrant for Mr. Brown’s arrest.

The Cherokee Nation’s response was astounding: It not only defended Mr. Brown’s defiance of court orders in South Carolina, where it too litigated this case for more than three years; it also responded by promising a new wave of lawsuits in Oklahoma and in tribal court and refusing to disclose Veronica’s location to law enforcement authorities. Ominously, a law school dean who works with Indian tribes told the Tulsa World, a local paper, that “South Carolina has made its decision. Now let’s see if they can enforce it.”

This display of bravado, of course, is supposed to echo a frequent misquotation of President Andrew Jackson’s response to the Supreme Court’s decision in Worcester v. Georgia, “John Marshall has made his decision. Now let him enforce it.”

But the invocation of President Jackson here is ironic: Worcester limited the effect of state laws on tribal lands — specifically, Cherokee lands.

To be sure, Chief Justice Marshall did not immediately enforce his decision — he did not send the federal marshals to Georgia — but the rule of law ultimately prevailed, and only because it did do Native American tribes now enjoy a measure of sovereignty.

So it’s puzzling that the Cherokee Nation and its supporters now seem so eager to disregard the rule of law, turn its tribal courts into kangaroo star chambers, and threaten disobedience. That’s irresponsible governance under any circumstances. But with a 4-year-old child at stake, it is unconscionable.

Do they really want a repeat of the Elian Gonzalez debacle?

The Cherokee Nation’s leaders should start acting like adults and start thinking about how their futile displays of defiance will affect the little girl in their care.

Theane Evangelis is a partner in Gibson, Dunn & Crutcher in Los Angeles, Calif. She represented amici child advocacy organizations in the U.S. Supreme Court in support of Veronica’s adoption. She is not involved as an attorney in the current dispute.