From a reader…
Can the priest celebrant of Mass tell a deacon tell a deacon to not wear a dalmatic at Mass? Some people think it best that a deacon wear a dalmatic for a higher degree of solemnity but not on common ferial days unless preaching. I imagine this might not be worth bickering over for transitional deacons, but what can a permanent deacon do?
“Higher degree of solemnity”. That sounds like that old chestnut of “progressive solemnity”.
B as in B, S as in S. That’s just liturgical stinginess.
The proper vestment of the priest is the chasuble.
The proper garment of the deacon is dalmatic.
The priest cannot be prevented from wearing his chasuble and the deacon his dalmatic.
As far as wearing it only when preaching is concerned, it is ironic that there is an old tradition of priests and deacons removing their chasuble or dalmatic to preach!
Of course when a priest has decided to make Mass about himself (“See? I get to wear a chasuble and HE only gets a stole!”) there is not much you can do. This is an exercise of power, which suppresses commonsense.
I suppose that you have already tried to win him over. With charm, keep working on it.
You might consider, when you have the chance to preach, explaining the significance of vestments and how the different offices require them in her sacred liturgical worship.