Question:
May a man who is a Cohen claim conscientious objection to war because he is not permitted to come into contact with dead bodies?
Answer:
The general theory back of the answer is that Cohanim nowadays are presumed by the bulk of rabbinical authority not to be of sure priestly descent. Nevertheless, though they are the first to be called to the Torah, this is out of courtesy, and Jacob Emden believes that because of the doubt they must return the money that is given them for the Pidyon Haben.
However, the old priestly laws that a priest avoid defilement by contact with the dead are still observed. The question is to what extent this customary observance of the law of uncleanliness with regard to the dead is sufficient ground for claiming conscientious objection to war.
A soldier may not necessarily come in contact with the dead at all. He is drafted and therefore must be considered an Anoos, and he certainly cannot refuse to serve upon this basis.