Stepsiblings and half-siblings are allowed, but not nieces or nephews. Sons- and daughters-in-law are in, but brothers- and sisters-in-law are not. Parents, including in-laws, are considered “close family,” but grandparents are not.

The State Department issued new guidelines on Wednesday night to American embassies and consulates on how they should enforce a limited travel ban against foreign visitors from six predominantly Muslim countries. Enforcement of the guidelines will begin at 8 p.m. Eastern on Thursday.

The guidelines followed the Supreme Court’s decision on Monday to allow parts of the Trump administration’s revised travel ban to move forward, while also imposing certain limits, as the court prepares to hear arguments in October on the scope of presidential power over border security and immigration.