Defense Secretary Pete Hegseth in a memo this month cemented restrictions on when, where and how the military and Pentagon leaders can engage with the public, noting that past "external engagements have tended to canalize toward certain types of institutions."

Why it matters: It's the latest evidence of a Defense Department clampdown amid internal concern about leaks, palace intrigue and narrative control.

• The Trump administration is obsessed with appearances. (Think about the president's "central casting" refrain and, more recently, his "Department of War" executive order.)
• The memo arrived around the same time the Defense Department rolled out new media guidelines that require reporters to sign a pledge not to gather any information that hasn't been officially authorized for release, or risk losing their press credentials.

Zoom in: The Sept. 15 memo to senior Pentagon leadership, combatant commanders and other national-security leaders lays out what is and what isn't subject to an "enhanced framework for participating in external engagements."

• The guidelines are written in a broad way that gives the department latitude to turn down speaking gigs or other gatherings that could generate unfavorable news.
• For example, the department reserves the right to reject any external engagement with an organization or person that hasn't displayed "professionalism." The memo states that DOD will "prioritize engagements with organizations that comport themselves professionally — even if they disagree with the Department's positions."
• The guidelines also put an emphasis on engagements that have "broad audiences" to ensure it's able to share information "widely, accurately, and as effectively as possible, consistent with the Department's commitment to transparency" and to ensure that personnel can "hear and learn from a wide range of perspectives."
• The memo notes that this guidance "does not require engagement solely with institutions that align with the Department's viewpoints" and that it will "make a concerted effort to engage with institutions whose representatives possess differing perspectives."

Of note: The military has long had protocols in place for speakers, conferences and interviews, among other outlets.

• "This past July, the Department of War's Office of Public Affairs began a process to thoroughly vet all external engagements to ensure the Department does not lend its name and credibility to organizations, forums, and events that run counter to the values of this administration. Our new procedure streamlines the approval process by providing principles that each engagement should uphold in order to allow DOW participation," Pentagon spokesperson Sean Parnell said in a statement.

Zoom out: This is part of a broader effort to put a tighter lid on the information that comes out of the Pentagon.

• The Defense Department in February replaced the press offices of several mainstream organizations with mostly conservative outlets.
• It informed several outlets — including NPR, NBC News, Politico and CNN — that they had to move out of their workspaces at the Correspondents' Corridor in the Pentagon, although their press credentials would remain intact.
• They were replaced by mostly conservative outlets such as Washington Examiner, Daily Caller, Newsmax and others under a new rotation system.

Flashback: Military speakers were pulled last-minute from major events on well-established speaking circuits, including the Aspen Security Forum and Defense News Conference.

• Hegseth has also repeatedly appeared on the Fox network.

Go deeper: The Pentagon's dramatic divorce from D.C. orthodoxy