A little decorum is always necessary.

Dulce et decorum est pro patria mori.

We'll be the models of decorum. Now, where's the punch?

He who knows not proper decorum must not rise to his feet.

In such an atmosphere, inclusion of politically incorrect content is not merely a risky move, but constitutes a breach of social decorum.

In his book The Blue Nile, Alan Moorehead described the expedition thus It proceeds first to last with the decorum and heavy inevitability of a Victorian state banquet, complete with ponderous speeches.

In fact, one has to search the books of diplomatic history to find evidence of non performance of diplomatic conventions , and in each instance the challenge to diplomatic decorum came from a source that can be credibly dismissed as barbarian.