make a decision
決定を下すのは彼の権限だ。
It is within his authority to make the decision.
これは難しい問題で、決定を下すのは誰にとっても容易なことではありません。
This is a difficult problem, and making a decision is not easy for anyone.
決定を下す前に事実をよく知らなければだめです。
You need to know the facts well before making a decision.
問題は誰が決定を下すかということだ。
The issue is who makes the decision.