Independency and efficacy of the surveillance panel are extremely important.

Independency and efficacy of the surveillance panel are extremely important.
監視委員会の独立性と実効性が極めて重要だ。

To strike a good balance between the preservation of state secrets concerning national security and the freedom of the press, it is indispensable for the surveillance panel to put the brakes on arbitrary designations of secrets by government ministries and agencies with an iron fist.
国の安全保障に関わる国家機密の保全と報道の自由とのバランスを上手くとるには、監視委員会が、各省庁が強権的に行う恣意的な指定に歯止めをかけることが不可欠だ。

efficacy 実効性
strike a balance between A and B
A と Bのバランスをとる
put the brakes on 〜に歯止め(待った)をかける
arbitrary 恣意的な
with an iron fist 強権的に 強権をもって