The title really says all that needs to be said. The font can be seen in documents from the Pentagon and White House around the 60s - 70s (link included). Though it is similar, it is not Copperplate Gothic (as you can see from the letterhead). Additionally, I've found "Aviano Sans" which is the closest match so far (looks very similar but isn't the same font, you can tell based off the M).

Help would be appreciated, thanks!

https://www.docsteach.org/documents/document/memorandum-no-52-vietnam

Sackers Gothic Medium is close, though 'Washington' is stretched

https://www.myfonts.com/fonts/mti/sackers-gothic/

There are a number of wide sans serifs designs meant for letterheads, usually with small caps instead of lowercase. Not all of them survive in digital format (and, of those that do, only a specific point size was digitised). The better known include the already suggested Sackers Gothic, Engravers Gothic, Blair, Wedding Gothic (wrong |R| in this case).

 

3 hours ago, Jack_Cabot said:

"Aviano Sans" which is the closest match so far (looks very similar but isn't the same font, you can tell based off the M).

Also because Aviano Sans is an original design from 2007.

39 minutes ago, Les said:

Sackers Gothic Medium is close, though 'Washington' is stretched

The “lowercase” is wider.

download at MyFonts

 

Ah, well spotted Riccardo! I think that pretty much solves it.

8 hours ago, Riccardo Sartori said:

There are a number of wide sans serifs designs meant for letterheads, usually with small caps instead of lowercase. Not all of them survive in digital format (and, of those that do, only a specific point size was digitised). The better known include the already suggested Sackers Gothic, Engravers Gothic, Blair, Wedding Gothic (wrong |R| in this case).

 

Also because Aviano Sans is an original design from 2007.

For the digital version (second two) Blair ITC is just about a perfect match. For the White House one, Sackers Gothic is the closest I think there is. Much appreciated.