A snippet of the NYT piece:

The Marine Corps said it was not uncommon to encounter politicians using the Eagle, Globe and Anchor, commonly referred to as the E.G.A., and officials routinely send letters telling them to stop.

“We encourage such individuals to be proud of their service,” the Marine Corps said in a statement. “But the use of the E.G.A. or other indicia, where it could appear that the Marine Corps endorses or sponsors a particular candidate, is inappropriate.”