Follow-up question to What does this sentence about Trump's lawsuits in Pennsylvania mean?

The document cited by Nate Eldredge in the answer to that question says:

Federal courts are not venues for plaintiffs to assert a bare right “to have the Government act in accordance with law.” Allen v. Wright, 468 U.S. 737, 754 (1984), abrogated on other grounds by Lexmark Int’l, Inc. v. Static Control Components, Inc., 572 U.S. 118, 126–27 (2014). When the alleged injury is undifferentiated and common to all members of the public, courts routinely dismiss such cases as “generalized grievances” that cannot support standing. United States v. Richardson, 418 U.S. 166, 173–75 (1974). Such is the case here insofar as Plaintiffs, and specifically candidate Bognet, theorize their harm as the right to have government administered in compliance with the Elections Clause and Electors Clause.

This seems to say that if the government does not act in accordance with law, private citizens cannot file suit to force it to do so. But if the government is not acting in accordance with law, presumably someone/something would be legally empowered to force the government to obey the law. What is that entity? What happens if that entity does not file suit?

Offhand, the closest example that I can think of is when the UK government passed a bill that would break international law, but that is obviously different -- that case involved international law and the aggrieved country would presumably file a lawsuit with the International Court of Justice.