“Bona fide relationship” is the new standard for the Trump administration’s travel ban, which goes into effect tonight at 8 p.m ET.

Now, people from the six countries targeted by the ban — Syria, Yemen, Iran, Libya, Somalia, and Sudan — have to prove a “bona fide relationship” with a person, an institution, or event in the US before they can visit, according to the ruling handed down by the Supreme Court.   

President Donald Trump first tried to enact a travel ban in January, weeks after taking office, but it was quickly struck down by courts. A new ban, issued in early March, removed Iraq from the list of banned countries and altered the wording of the executive order. That ban was then struck down by lower courts, but was temporarily reinstated on Monday by the Supreme Court, which will weigh its legality in a full hearing in October.

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Monday’s ruling limits the initial travel ban while it goes into effect for the next 90 days for immigrants and 120 days for refugees.

It will also likely lead to confusion and bureaucratic obstacles for immigrants and refugees trying to enter the country by showing that they have a “bona fide” relationship with people already in America, advocates said this week.

What will the standard of proof be for “bona fide relationship?”

The Trump administration tried to clear up the expected confusion by outlining what constitutes a “bona fide relationship” in a cable sent to US embassies.

It’s also trying to curb the potential use of the term.

Some of the “bona fide relationships” are obvious: a parent, spouse, child, son-in law, daughter in-law, or sibling, but the cut-off mark seems arbitrary to many legal experts, who said they expect lawsuits to follow.

Those excluded from the world of bona fide relationships include fiancees, grandparents, grandchildren, aunts, uncles, nieces, nephews, cousins, brothers-in-law, sisters-in-law, and any extended family members.

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"This whole close family ties — it's a very dangerous thing to talk about or to use as a basis to get a visa," Reaz Jafri, a partner and the head of the global immigration practice at the Withers Bergman law firm, told Business Insider. "My sense is that it just creates massive confusion as to who's going to get in. Only employees, students, people who have had green-card cases processed overseas are going to be let in. Everyone else, in my opinion, are going to be out of luck."

As Jafri said, there are clearer lines of entry for those connected to institutions. Students admitted to American universities, workers hired by American companies, and lecturers invited to speak to American audiences are allowed entry in the country.

Building on previous adjustments to the ban, the administration also spelled out that certain groups are not to be excluded on any grounds. These include: US citizens, green card holders, current visa holders, any visa applicant who was in the US as of June 26, dual nationals, anyone granted asylum, and any refugee already admitted to the US.

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The Supreme Court will hear the case in October. By then, the travel ban could be further crippled by new lawsuits.

Either way, the effect it’s having on US immigration is continuing far past its initial 90-day window.