Reply #6: Here is the policy.

[MissMarple]

http://www.dtic.mil/whs/directives/corres/html2/d134410x.htm

4. POLICY It is DoD policy to encourage members of the Armed Forces (hereafter referred to as "members") to carry out the obligations of citizenship. While on active duty, however, members are prohibited from engaging in certain political activities. The following DoD policy shall apply: ...

4.1.1. A member on active duty may: ...
4.1.1.3. Attend partisan and nonpartisan political meetings, rallies, or conventions as a spectator when not in uniform.

4.1.2. A member on active duty shall not:

4.1.2.1. Use his or her official authority or influence for interfering with an election; affecting the course or outcome of an election; soliciting votes for a particular candidate or issue; or requiring or soliciting political contributions from others. ...

4.1.2.3. Participate in partisan political management, campaigns, or conventions (unless attending a convention as a spectator when not in uniform).

4.1.2.4. Make campaign contributions to another member of the Armed Forces or an employee of the Federal Government. ...

4.4.4. A member who violates any of the prohibitions in subparagraphs 4.1.2., 4.2.1., 4.3.1., or 4.3.4., or enclosure 3, of this Directive may be subject to disciplinary or adverse administrative action under Service regulations. ...

E3.3. EXAMPLES OF PROHIBITED POLITICAL ACTIVITIES

E3.3.8. Speak before a partisan political gathering, including any gathering that promotes a partisan political party, candidate, or cause.