Trump shows little direct interest in conservative jurisprudence, except as it affects him directly or is useful as a political tool. As a result, McGahn had broad leeway to handle the judgeships as he wanted, as Jason Zengerle recently reported in The New York Times Magazine:
As White House counsel, McGahn has exercised an unprecedented degree of control over judicial appointments. In previous White Houses, both Republican and Democrat, judicial nominations were typically crowdsourced among officials from different parts of the administration … Under Trump, the job belongs exclusively to the White House Counsel’s Office, with McGahn and his deputy, Robert Luther, and about 10 associate counsels identifying and then scrutinizing candidates. This process is unique in White House history.
McGahn worked hand in glove with the conservative Federalist Society, producing one of the Trump administration’s most successful initiatives, despite a few hiccups.