Regarding your question about military service, the Guardian sees no reason why the Bahá’í in question should not bring a test case, and press the matter. It is now, since he has become a follower of Bahá’u’lláh, against this conscience to kill his fellow-men; and he should have the right to explain his position and ask to be exempted from combatant service. During the hearing of such cases, the Bahá’ís should make it absolutely clear that we do not fear being placed in danger, and are not asking to be given a safe berth in hours of national crisis -- quite the contrary -- any dangerous service that Bahá’ís can render their fellow-men during the agonies of war, they should be anxious to accept.

Shoghi Effendi, Lights of Guidance, p. 408

The other main objection to the conscientious objectors is that their method of establishing peace is too negative. Non-cooperation is too passive a philosophy to become an effective way for social reconstruction. Their refusal to bear arms can never establish peace. There should first be a spiritual revitalization which nothing, except the Cause of God, can effectively bring to every man’s heart.

Shoghi Effendi, Directives from the Guardian, no. 144

There are many other avenues through which the believers can assist in a time of war by enlisting in services of a non-combatant nature - services that do not involve the direct shedding of blood - such as ambulance work, air raid precaution service, office and administrative works, and it is for such types of national service that they should volunteer.

It is immaterial whether such activities would still expose them to dangers, either at home or in the front, since their desire is not to protect their lives, but to desist from any acts of willful murder.

Shoghi Effendi, in Principles of Bahá’í Administration, p. 95–96

With reference to the absolute pacifists, or conscientious objectors to war; their attitude, judged from the Bahá’í standpoint, is quite anti-social and due to its exaltation of the individual conscience leads inevitably to disorder and chaos in society. Extreme pacifists are thus very close to the anarchists, in the sense that both of these groups lay an undue emphasis on the rights and merits of the individual. The Bahá’í conception of social life is essentially based on the subordination of the individual will to that of society. It neither suppresses the individual nor does it exalt him to the point of making him an anti-social creature, a menace to society. As in everything, it follows the “golden mean.” The only way that society can function is for the minority to follow the will of the majority.

Shoghi Effendi, Directives from the Guardian, no. 144

Bahá’ís recognize the right and duty of governments to use force for the maintenance of law and order and to protect their people. Thus, for a Bahá’í, the shedding of blood for such a purpose is not necessarily essentially wrong. The Bahá’í Faith draws a very definite distinction between the duty of an individual to forgive and “to be killed rather than to kill” and the duty of society to uphold justice. This matter is explained by ?bdu'l-Bahá in Some Answered Questions. In the present condition of the world Bahá’ís try to keep themselves out of the internecine conflicts that are raging among their fellow men and to avoid shedding blood in such struggles, but this does not mean that we are absolute pacifists.

Universal House of Justice, Lights of Guidance, no. 1354

Sanctions should not be imposed for violation of these instructions. It is for each believer, under pain of his own conscience, to determine for himself what his actions should be, bearing in mind that the application of these principles is the spiritual obligation of every Bahá’í. It is rather for your Assembly to see that adequate instruction is provided so that the friends will let these principles be mirrored forth in their actions, and that they will be so steadfast in their love for Bahá’u’lláh that it would be unthinkable for them to willingly place themselves in a position where they must take human life.

Universal House of Justice, NSA USA - Developing Distinctive Bahá’í Communities