Well, it would help there were a crime to prosecute. Mueller tried for two years and failed. The Jan 6th show also struck out. It's not for lack of effort.
While it has taken far too long, the work of investigators, grand juries, prosecutors and litigants is beginning to bear fruit.
1. The Manhattan grand jury issued a criminal indictment for filing false documents. Trump surrendered for arrest and was charged. That case is now working its way through court.
2. The Fulton County DA announced that charging decisions will be made this summer.
3. The Jan 6 grand jury seems to be nearing the end of its work as they have worked their way up the witness list, hearing from Trump's former vice president and chief of staff. There are no higher-ranking Trump administration officials to hear from. We have heard of no recent subpoenas issued by that body. That suggests indictments may be coming soon.
4. It appears to be the same with the grand jury investigating the Mar-A-Lago documents case. All high-ranking witnesses have appeared before the grand jury. We know of no new subpoenas recently issued.
5. While Trump was not personally charged, the Manhattan DA succeeded in convicting his company, the Trump Organization, of the crime of tax fraud.
6. While it was a civil case, a jury recently found Trump liable for the crimes of defamation and sexual abuse regarding E. Jean Carroll. They ordered Trump to pay Carroll $5 million in damages.
7. While it is a civil case, Trump has been accused of crimes by the NY State AG. That case is fully developed and filed. It is currently making its way through court.
8. Under the inherent authority they have, two different judges have imposed sanctions on Trump for misconduct during the litigation process. In one case, plaintiff Trump was fined nearly $1 million dollars for bringing a frivolous lawsuit against 31 defendants. The money went to the defendants to pay their legal costs; $172,000 of that went to Hillary Clinton. In the other case, Trump paid $110,000 in fines for his failure to comply with a subpoena (issued by the NY State DA). While these are not crimes per se, judges have said Trump's behavior was misconduct and he was sanctioned because of it. Those sanctions seem to have had an effect. Trump has not filed a frivolous lawsuit subsequent to those fines.