Veteran Pentagon reporter Lolita C. Baldor used strong source work to break the news that members of the U.S. military will be required to get the COVID-19 vaccine under a Pentagon plan endorsed by President Joe Biden.

Baldor spoke to contacts every day on the issue, and while some news outlets reported incorrectly that the Pentagon announcement would come Aug. 6, Baldor’s sources told her the decision was being pushed to the following week because of legal wrangling at the White House.

She prepped a story on Friday, then got word mid-morning on Monday that an announcement was expected later in the day. Then she kept making calls until a longtime source gave her the memo on the condition that the story be held briefly so Congress could be notified.

Immediately after AP’s alert, Baldor had a full story on the wire with quotes from the memo explaining the rationale behind the vaccine policy. AP was the only news organization to get the memo and was first with the story and details, sending competitors scrambling to catch up; many news organizations cited AP as the news broke. The story had the most pageviews of the day on the AP News app and site, with more than three times the views of the No. 2 story.