This is going to also impact the arguments made by other Trump associates against testifying. 

Courtesy of NPR:

A federal judge in Washington has ruled that former White House counsel Don McGahn must testify to House impeachment investigators, despite orders from the Trump administration that he not cooperate with Congress.

The decision by U.S. District Judge Ketanji Brown Jackson clears the way for McGahn’s testimony sought by House Democrats in exploring Trump’s possible obstruction of justice related to the Russia probe.

Jackson declared in her 118-page ruling that “no one is above the law.”

She added: “However busy or essential a presidential aide might be, and whatever their proximity to sensitive domestic and national-security projects, the President does not have the power to excuse him or her from taking an action that the law requires.”

The ruling could have implications for other key witnesses, such as former national security adviser John Bolton who has refused to testify until a federal court weighs in on the conflict between Congress and the White House.

The Trump administration is expected to appeal.

Of course they are going to appeal, but I think ultimately the appellate courts are going to agree with this judge. 

Right now the Trump folks are simply delaying the inevitable.

They know that the hammer is going to fall but they are putting it off for as long as possible.  

I once again have to ask, “Does Trump ever win a court case?”