nA party seeking judicial review of a law must have standing to challenge that law, which means that the operation of the law must produce a substantial injury
to the rights of the party
nA federal taxpayer who believes that a particular
federal program is
unconstitutional does not normally have standing to challenge the law on which the program is based.
nOne who is prosecuted criminally under an arguably unconstitutional statute has standing to challenge that statute.
nOne who is likely to be prosecuted or whose activities are chilled or deterred by the existence of a statute
can bring a civil suit
seeking to enjoin enforcement of the law.