After the SCOTUS ruled that local fed judges can't put in a national injunction against Trump's EO... especially the birth-right citizenship. The Court did not ruled whether that rule is constitutional or not... just that local judges do not have the power to put a national injunction against it.
If you don't know about the birthright citizenship is... it's about baby being born on US soil to illegals/visa holder/tourist automatically becoming a US citizens. Many, many wealthy people around the world abused this rule by coming to the US just prior to giving birth and staying long enough to give birth to a brand new US citizen baby

with all the benefits.
Now, the ACLU is suing Trump over this... in their class action lawsuit, the ACLU, in their argument said that they must certify a class of persons for this suit because of the Supreme Court ruling... and that class of person IS (drum roll, please) all 'future persons' - potential humans being represented before this court... Uh, you mean the unborn? You are fighting for the unborn? Wait, wait, wait... I thought the ACLU, abortion right activists and Lefties/Demmies all told us that the unborn is just a lump of cell and not a human and has not right. Now, they're suing Trump on behalf of the unborn that will get affected by Trump's EO