sine qua non

The Japan Times September 4の記事 "The key to winning in Afghanistan" からの抜粋です。
Islamabad's proxy jihadis cannot be defeated with half measures. And yet, we have coddled Pakistan as an important ally in the war against al-Qaida and the Taliban, even though it is essentially an enemy that has acted in ways fully inimical to the coalition’s troops, its Afghan allies and the aims of the Afghan state.
"half measures" は中途半端な手段の様な意味だと推測できますが、日本語の中途半端な手段からこの英語は知らないと出てきませんね。一応辞書で確認します。
・Collins Dictionary: inadequate measures or actions: They have already declared their intention to fight on rather than settle for half-measures.
・Cambridge English Dictionary: actions that only achieve part of what they are intended to achieve: I'm not interested in half measures.
記事の後半からも一部を抜粋します。
It is only possible for Pakistan to become a genuine strategic partner to the U.S. if it changes, and eschews its support of proxy terrorists and insurgents. The sine qua non for a win is to shut down the sanctuary and the external support from Pakistan.
"sine qua non" は以前取り上げた気がするのですが、記録がありません。そこで再度辞書の説明を引用します。
・Oxford English Dictionary: An essential condition; a thing that is absolutely necessary.: grammar and usage are the sine qua non of language teaching and learning
・Cambridge English Dictionary: a necessary condition without which something is not possible: An interest in children is a sine qua non of teaching.