In the mid 1930s, the Watch Tower Society started forbidding Jehovah's Witnesses to salute the American Flag, or recite the Pledge Of Allegiance, or stand for the playing of the National Anthem, or engage in any other patriotic activity.
Jehovah's Witnesses were taught to tell the news media, courts, and other outsiders that the American Flag is a false idol, and doing any of the aforementioned activities is performing "worship" to a false idol. This "public relations" reasoning is actually the LEAST of all the reasons that Jehovah's Witnesses refuse to engage in any patriotic or political activities. This secondary, ancillary reasoning was developed because the WatchTower Society did not dare to have its Jehovah's Witness members running around repeating for the news media and courtroom judges the PRIMARY doctrine on this subject, which would outrage the American public.
What Jehovah's Witnesses intentionally do NOT publically explain to non-JWs is that the Watch Tower CULT teaches Jehovah's Witnesses that the Government of the United States is governing ILLEGITIMATELY.
The WatchTower Cult teaches that the Government of the United States is under the control of Satan the Devil as his partner in Satan's universal rebellion against GOD. The Watch Tower Society teaches that GOD granted humans the authority to rule the earth only for a period of 2520 years -- starting in 607 B.C. and ending in October, 1914 A.D. The Watch Tower Society teaches that in October, 1914, the authority to rule the earth reverted back to GOD, and that He then formed a heavenly government to rule the earth.
The WatchTower Cult teaches that in 1919 that Jesus Christ selected the WATCHTOWER CULT as his sole earthly representative of that heavenly government.
The WatchTower Cult teaches that the Government of the United States (as well as all other governments), is its' enemy, because it has failed to surrender governmental power that rightfully belongs to the Watch Tower Society.
These are the ACTUAL reasons that the WatchTower Cult forbids its Jehovah's Witness members to support the government of the United States -- no voting, no holding political office, no professing citizen loyalty via the Pledge of Allegiance or standing for the National Anthem, no joining the military to protect the United States, etc.
The WatchTower Cult teaches that Armageddon will occur "soon", and at the Battle of Armageddon, that Jesus Christ and his heavenly armies will destroy the armies and governments of the United States, and of all other countries -- including all people who did not convert to the Jehovah's Witnesses.
Jehovah's Witnesses look forward to the day when they will rule the planet.