Whether a religious order can be directed to soldiering?

Objections

Objection 1 : It would seem that no religious order can be directed to soldiering. For all religious orders belong to the state of perfection. Now our Lord said with reference to the perfection of Christian life (Mt. 5:39): "I say to you not to resist evil; but if one strike thee on the right cheek, turn to him also the other," which is inconsistent with the duties of a soldier. Therefore no religious order can be established for soldiering.
Objection 2 : Further, the bodily encounter of the battlefield is more grievous than the encounter in words that takes place between counsel at law. Yet religious are forbidden to plead at law, as appears from the Decretal De Postulando quoted above (Article [2], Objection [2]). Therefore it is much less seemly for a religious order to be established for soldiering.
Objection 3 : Further, the religious state is a state of penance, as we have said above (Question [187], Article [6]). Now according to the code of laws soldiering is forbidden to penitents. for it is said in the Decretal De Poenit., Dist. v, cap. 3: "It is altogether opposed to the rules of the Church, to return to worldly soldiering after doing penance." Therefore it is unfitting for any religious order to be established for soldiering.
Objection 4 : Further, no religious order may be established for an unjust object. But as Isidore says (Etym. xviii, 1), "A just war is one that is waged by order of the emperor." Since then religious are private individuals, it would seem unlawful for them to wage war; and consequently no religious order may be established for this purpose.