Transcript for White House orders its former lawyer not to comply with congressional subpoena
between the president and some members of congress. They now want to know what white house counsel don mcgahn witnessed inside the white house. He revealed a lot to Robert Mueller, but this question -- will he reveal it to the American people? Not if the president has his way. And here's ABC's Cecilia Vega. Reporter: He was the white house lower on the inside. The man who heard it all and took notes on everything. And today, the trump administration made it clear it does not want don Mcghan cooperating with congressional investigators, ordering him not to comply with a subpoena demanding his records from the Mueller probe. Democrats are enraged. Every day, he's obstructing justice by saying this one shouldn't testify and that one shouldn't testify. Reporter: Mcgahn played a key role in the special counsel's investigation into whether president trump obstructed justice. Cited more than any other witness in the Mueller report, 157 sometimes. He told report Mueller's team the president repeatedly asked him to have Mueller fired. Mcgahn said he refused and also refused to lie about it later. And he documented it all in extensive notes. Today, in a letter to the house judiciary committee, the current white house counsel wrote mcgahn was allowed to share his records with Mueller with clear understanding that the records remain subject to the control of the white house for all purposes. The president has already implied he'll try to block mcgahn from testifying. I don't think I can let him and then tell everybody else you can, because especially him because he was a counsel. Reporter: Democrats are bracing for a long showdown. Trump is goading us to impeach him. That's what he's doing. Every single day, he's just like taunting, taunting, taunting. Cecilia Vega live at the white house tonight. And Cecilia, congress wants to see don mcgahn's notes, they want him to testify, as you just reported there, but what kind of legal standing does the white house have to try to block this from happening? Reporter: Well, David, the white house seems to be gearing up to exert executive privilege, blocking don mcgahn from testifying on certain topics. The Democrats are certain to challenge that. They say that president trump gave up his executive privilege card when he allowed don mcgahn to participate in the Mueller probe. One thing seems certain tonight, we are likely looking at a long legal fight ahead. All right, Cecilia, thank you, as always. Tonight, Georgia has now
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