When the Carter Page FISA application was originally assembled by the FBI and DOJ, there was initial hesitancy from within the DOJ National Security Division (DOJ-NSD) about submitting the application, because it did not have enough citations in evidence (the infamous ‘Woods File’). That’s why the Steele Dossier ultimately became important. It was the Steele Dossier that provided the push, the legal cover needed for the DOJ-NSD to submit the application for a Title-1 surveillance warrant against the campaign of Donald J. Trump.

When the application was finally assembled for submission to the FISA court, the head of the DOJ-NSD was John Carlin. Carlin quit working for the DOJ-NSD in late September 2016 just before the final application was submitted (October 21,2016). John Carlin was replaced by Deputy Asst. Attorney General, Mary McCord.
♦ When the FISA application was finally submitted (approved by Sally Yates and James Comey), it was Mary McCord who did the actual process of filing the application and gaining the Title-1 surveillance warrant.
A few months later, February 2017, with Donald Trump now in office as President, it was Mary McCord who went with Deputy AG Sally Yates to the White House to confront White House legal counsel Don McGahn over the Michael Flynn interview with FBI agents. The surveillance of Flynn’s calls was presumably done under the auspices and legal authority of the FISA application Mary McCord previously was in charge of submitting.
Dear fellow Americans:

While the topic is downplayed by U.S. corporate media, the specifics of the issue are pertinent in that they highlight the politicization of the Justice Department by DOJ officials throughout main justice and the various offices of U.S. attorneys.