at issue
most important in what is being discussed:
The point at issue is what is best for the child.

[TahlilGaran] Advanced Learner's Dictionary ▲

at issue
1.
not decided.
At issue is whether Linda broke state law by secretly taping conversations.

2.
in disagreement.
What is at issue is how the organization spends its money.

[TahlilGaran] English Idioms Dictionary ▲

at issue
adj. phr.
1. In dispute; to be settled by debate, by vote, by battle, or by some other contest.
His good name was at issue in the trial.
The independence of the United States from England was at issue in the Revolutionary War.
Compare: IN QUESTION.
2. Not in agreement; in conflict; opposing.
His work as a doctor was at issue with other doctors' practice.
Synonym: AT ODDS.

[TahlilGaran] English Idioms Dictionary ▲