I wonder, if the Republicans controlled the House, whether there would already be an impreachment inquiry open. Mueller served the role as investigator, collecting evidence and documenting his findings. The Constitution gives the House the job of prosecuting attorney (not the Attorney General) in determining whether to charge the President with a crime, which for the President has the unique label of impreachment.
A Republican inquiry would review the evidence, formally declare there is none to bring charges, and then the case is closed. Until the House says it is closed, the case is not closed no matter what Trump or Barr says. That is the Constitution.
To uphold their oath to the Constitution, Democrats in the House must open the impeachment inquiry and determine whether or not to vote articles of impeachment. They must be willing to take the political risk, if that exists, to fulfill their role in our government. It’s not about politics, it’s about the rule of law.
In fact, I think Congress should produce new presidential special consule legislation that states that all presidential special consule investigations require an impeachment inquiry to formalize the conclusions of the investigation.
If the criminal justice system cannot bring charges against a sitting president then Congress has to take serious this responsibility. That is unless Congress thinks the President really is above the law.