As I recall from some passages, there were times when a priest had to anoint a war-leader... not necessarily a king, but sometimes a dedicated warrior to handle an emergency. Can an expert in sword (either broadsword where sitting vigil is a Christian dedication ritual, or even such as katana where an expert not answering to a master is considered by the culture of that training to be 'ronin', masterless or undedicated) choose to dedicate him or herself to the defence of the Jewish People, and does a Kohen still have the power as a descendant of priests to perform that dedication?
Sorry, nothing that grandiose.
There was a civilian Kohen Gadol (high priest), and then there was his military equivalent, known as the mashuach milchama -- the Kohen appointed for war. The mashuach milchama's job was basically to give the troops a big sermon before the battle, that's about it. He was given the Kohen Gadol status the same way his civilian counterpart was -- either through special anointing oil, or through wearing the special clothes for a few days.
As today there's no Temple, there is neither civilian Kohen Gadol nor a mashuach milchama (though obviously, today's Israeli Defense Forces have rabbi chaplains).