President Donald Trump’s administration has issued guidelines through the State Department for who will be exempt from the travel ban from six majority Muslim countries, which the US Supreme Court allowed Monday to partly go into effect. The guidelines are highly arbitrary in defining what counts as a family relationship that merits exemption. For example, your mother-in-law is close enough to come into the US, but not your grandmother, a blood relative without whom you wouldn’t exist.

That’s because the Trump administration wants to keep out as many people as it can. But it’s also the result of the Supreme Court’s decision, which created a brand new legal category of “bona fide relationship” while defining it only in connection with the plaintiffs in the case. The result will be practical difficulties as well as more litigation in the months before the justices directly address the legality of the ban.

When the justices ruled on the ban this week, they sought to craft a compromise that would preserve the temporary restrictions on the ban put in place by the lower courts while simultaneously allowing Trump to declare victory, as he in fact did.

The centerpiece of the compromise was that the travel ban would not apply to foreign nationals seeking admission to the US who have a “bona fide relationship with a person or entity in the United States.”

The court made up this category out of whole cloth. That’s allowed because the court has wide latitude to craft remedies when it is deciding on what will happen while litigation is pending. It’s exercising what is called “equitable discretion,” a legal phrase with roots in an old English legal distinction between strict law and flexible equity. When courts do equity rather than law, they don’t have to follow rules laid down in precedent or statute. They can weigh competing considerations and make up a rule to fit the specific case.

The upside of equity is that it’s flexible. The downside is that when courts make up new rules, those rules have to be applied by government officials who lack detailed guidance.

The justices told the Trump administration that there were two kinds of “bona fide relationships” that it must consider. The first was what the court called “close familial relationships,” which is said were “required.”

The court didn’t say much more than that about what counts as close. Its only examples were two of the original plaintiffs on the challenge to the ban: Ismail Elshikh, who sought to bring his mother-in-law to the US from Syria, and the unnamed plaintiff “John Doe,” who wants to bring his wife from Iran. The court wrote: “A foreign national who wishes to enter the United States to live with or visit a family member, like Doe’s wife or Dr. Elshikh’s mother-in-law, clearly has such a relationship.”

As a result of the Elshikh example, the Trump administration had no choice but to include parents-in-law and sons- and daughters-in-law in its guidelines. It also logically had to count children and siblings, who are closer than in-laws. And it made the choice to count “half” relationships including “step relationships.”

But the administration excluded grandparents and grandchildren, uncles and aunts, nieces and nephews, as well as unmarried partners, even when they are engaged.

It’s truly arbitrary to say your grandmother is not as a close a relative as your mother-in-law. Ditto your uncle.

It’s not that Trump likes his in-laws more than his grandparents. This arbitrariness is a direct product of the court’s mention of Elshikh’s mother-in-law. If he had been trying to get his grandmother in, grandparents would now be allowed — and I bet in-laws would have been out.

The Trump administration is trying to be as exclusionary as possible without violating the letter of the Supreme Court’s opinion.

Expect litigation over the grandmother issue — starting as soon as today.

Another potential legal issue is that none of the six countries has same-sex marriage, so the rule as written effectively discriminates against gay partners.

The Supreme Court may never rule on the arbitrariness issue. Its “close familial relationships” rule is only supposed to remain in place until the court addresses the merits of the travel ban in the fall. It may prefer to let the lower courts sort it out.

In the meantime, the anti-grandmothers rule stands as a testament to the Trump administration’s grudging attitude toward immigrants — and the limits of the court’s equitable approach to compromise in this case.

Bloomberg