When the Trump administration issued its first restrictions on refugees and on individuals from several majority-Muslim countries seeking to enter the United States, heartrending scenes of travelers separated from their loved ones caused protesters to flood airports and sparked lawsuits challenging the travel bans. One of the first, filed by Hawaii Attorney General Douglas Chin, is currently pending before the U.S. Supreme Court.

After lower courts blocked various executive orders, the Supreme Court on June 26 agreed to decide whether the bans are lawful. In the interim, the court ruled, the government may exclude only foreign nationals “who have no connection to the United States.” Those “who have a credible claim of a bona fide relationship with a person or entity in the United States,” including a “close familial relationship” to a U.S. individual, remain eligible to enter as refugees or apply for visas.

On June 29, the Trump administration issued guidance that narrowly defines “close familial relationship” to include parents, children, siblings and parents-in-law — but not grandparents, grandchildren, aunts, uncles, nieces, nephews, or cousins.

The administration guidance defies the constitutional tradition that honors the central importance of intimate family ties. In a landmark 1977 decision striking down an East Cleveland zoning ordinance that prohibited Inez Moore from taking in her orphaned grandson, Justice Lewis F. Powell, Jr. wrote for a majority of the Supreme Court: “Ours is by no means a tradition limited to respect for the bonds uniting the members of the nuclear family. The tradition of uncles, aunts, cousins, and especially grandparents sharing a household along with parents and children has roots equally venerable and deserving of constitutional recognition.”

The government’s cramped interpretation of close familial relationships adds another dimension to the grave constitutional questions raised by the travel ban: foremost, whether the president’s executive orders are unconstitutionally motivated by anti-Muslim animus, as statements by President Donald Trump and his surrogates strongly suggest, and as the Fourth Circuit Court of Appeals recently ruled.

As the Supreme Court emphasized in Moore, a child who has lost one or both parents often relies on other close family members to fill the emotional and material void. By defining “close familial relationships” to exclude aunts, uncles, cousins and grandparents, the Trump administration’s policy harms exactly those families in which such intimate bonds are most likely to have formed: those suffering the absence of a parent, adult child or sibling. Such losses are especially prevalent among refugee populations escaping civil war, violence and political persecution.

Even in families not so touched by loss, Justice Powell wrote, the Constitution places limits on the government’s ability to “slice deeply into the family itself.” Regardless of whether family bonds were forged in “personal tragedy,” he insisted, “the choice of relatives in this degree of kinship” — a grandmother and two cousins — “to live together may not lightly be denied by the State.”

The families affected by the administration’s narrow definition include those afflicted by unimaginable tragedy and those simply wishing to celebrate joyous occasions with their dearest relatives: A Syrian-born grandmother seeking refuge for her orphaned grandchildren in the United States; a naturalized citizen whose Yemeni grandfather cannot travel to the U.S. to receive medical care; an American-born woman whose only living relatives, Iranian aunts, uncles and cousins, cannot attend her wedding.

By arbitrarily excluding relatives who undeniably have a “credible claim to a bona fide relationship with a person or entity in the United States,” the Trump administration not only flouts the letter and spirit of the Supreme Court’s order, but disregards decades of jurisprudence recognizing the constitutional as well as the human value of family ties.

Serena Mayeri is a professor of law and history at the University of Pennsylvania Law School.