Is there a way for states to bring a criminal prosecution against Trump, if the Republicans won't?

[The Velveteen Ocelot]

32. That was a different situation. The state AGs were representing their clients,

which were the states themselves, and the entire case is civil and not criminal. There is no criminal prosecution of anybody; the question is the validity of Trump's EO. Since the EO was the act of a federal official, the states by their AGs had to go to federal court to argue that the EO harmed their states. Don't confuse prosecutorial power with federal jurisdiction; or civil cases with criminal cases. A state prosecutor (normally a district attorney, not the state AG) can prosecute acts that are criminal under that state's laws, and must do so in that state's courts. If a federal crime has been committed, e.g., espionage, a U.S. attorney would handle the prosecution in a federal court. Some acts are illegal under separate state and federal laws (e.g., some kinds of drug trafficking); in those cases the prosecution would be determined by agreement. A big drug case would probably go to the feds even though a state statute was also violated, as there are also issues of federal supremacy.

But the point, more simply put, is that state prosecutors can't and don't prosecute federal crimes in federal courts, though state AGs can and do represent their states in federal courts in civil matters where the federal government or a federal official is a party.