Democrats have been eager to hear from McGahn - a key figure in Special Counsel Robert Mueller's investigation who described ways in which the president sought to curtail the probe. Later, when news articles about the incident surfaced, McGahn told Mueller's investigators that Trump tried to get him to dispute the accuracy of the reports.
That is still possible, since the justice department's legal opinion does not prevent McGahn testifying if he so chooses, although it would be potentially at risk to his own career.
Trump's challenge of the Mazars subpoena was his first effort to quash the multiple House inquiries.
Nadler added that the committee hearing will continue as scheduled on Tuesday and they expect McGahn to testify "as legally required". Mehta ruled the committee's claims that Trump's records will help it consider strengthening ethics and disclosure laws and enforce a constitutional ban on acceptance of foreign gifts by a president were "facially valid", saying, "It is not for the court to question whether the Committee's actions are truly motivated by political considerations".
Doris Day: A life of style and glamour
In her 1976 tell-all autobiography, Doris Day: Her Own Story, Day described her squeaky-clean reputation as "unfortunate". There were a few would-be comebacks in the early 80s that never came to be, including a " Pillow Talk " sequel.
The president's critics said such an explanation may not hold up in court, and that might be the Democrats' next move in their war against President Trump.
Some Democratic Party leaders have argued that Trump's stonewalling represents a "constitutional crisis" and could force them to begin impeachment proceedings to remove him from office.
The White House made the same argument Friday when Treasury Secretary Steven Mnuchin said he would not comply with a congressional subpoena for six years of Trump's tax returns.
Trump's attorneys fire back that Democrats' true objective is not governance but political advantage, to expose the Trumps' "private financial information for the sake of exposure, with the hope that it will turn up something that Democrats can use as a political tool against the President".
The standoff deepened on Monday when Trump told former White House counsel Don McGahn to defy a subpoena to testify about Special Counsel Robert Mueller's Russian Federation investigation before a different congressional committee.
Many Democratic lawmakers, as well as many former prosecutors not involved in the investigation, have said the alleged order by the president to fire Mueller and attempt to coerce McGahn to lie about it could amount to committing the crime of obstruction. Trump has refused to turn them over citing an audit.
Trump has mused about instructing Republicans to cease dealing with the firm, which is deeply intertwined in Washington with the GOP, according to one White House official and a Republican close to the White House not authorized to speak publicly about private conversations.