Related to Ezra's dispatch from the YKos military panel, last week a Pentagon investigation concluded that several generals and a former military chaplain wrongly appeared in uniform in a fundraising video for Christian Embassy, a group affiliated with Campus Crusade for Christ. These soldiers are not permitted to endorse a "non-federal" entities.
When high-level generals endorse a politically charged religious group, it sets an example not only for lower officers, but leads the public to believe that the military and such groups go hand in hand. I'm okay with military officers expressing an opinion, but there's a fine line between an opinion and a flat-out endorsement, and the generals' appearance in the Christian Embassy video clearly exemplifies the latter. Especially when officers appear in uniform expressing an opinion, it tends to be seen as having the approval of the military branch.