To be clear, DHS was not required to do any of this or to
“consider all policy alternatives in reaching [its] decision.”
State Farm, 463 U. S., at 51. Agencies are not compelled to
explore “every alternative device and thought conceivable
by the mind of man.” Vermont Yankee Nuclear Power Corp.
v. Natural Resources Defense Council, Inc., 435 U. S. 519,
551 (1978). But, because DHS was “not writing on a blank
slate,” post, at 22, n. 14 (opinion of THOMAS, J.), it was required
to assess whether there were reliance interests, determine
whether they were significant, and weigh any such
interests against competing policy concerns.
The issue of reliance, I think, is important here - did ICE actually internally discuss the extent to which international students and their families were relying on the previous guidance, and did they actually do any kind of analysis that the benefit to society and economy would outweigh those reliance interests, even for non-citizens? Given that societal benefits are practically nonexistent and that many university systems economically rely on continuity of their matriculated student bodies, particularly international students paying non-subsidized tuition, it seems unlikely that such an analysis was done in good faith.
Yeah, we have a concept in common law called legitimate expectation that is quite similar to the point you're getting at. Don't know about the U.S.
Having recently been on the right side of a judicial challenge, I must say that in my non-lawyer view, it is quite a powerful check on a decision-maker's discretion.
