In the US legal system in general, the interests of the government are not trump cards. If the law says that the government should pay you $1000, it doesn't mat

In the US legal system in general, the interests of the government are not trump cards. If the law says that the government should pay you $1000, it doesn't matter whether the public or the government feel they have an interest in paying you, nor whether some executive official thinks the original purpose of that law is served by paying you. In this case, the law does give the executive some discretion to decide based on their priorities whether they really owe you $1000, but the plaintiffs argue the NSF has exceeded that discretion.