back to the drawing board 「振り出しに戻る」

前回の例文に出てきた with a clean slate は、文脈によって「白紙の状態で」と訳せるだろうが、「白紙」ということで back to the drawing board という表現を思い起こした。「振り出しに戻って」「一からやり直す」ととらえてもいいだろう。

次は私の学習メモから、以前取り上げたことがある "Rise of the Vulcans" というノンフィクションにあった実例である。

At the end of 1991 the Soviet Union broke up and disappeared. That sent Pentagon planners back to the drawing boards once again.

さらに、オンライン辞書にあった説明や例文を抜き書きしておこう。

- back to the original or an earlier stage of planning or development:
Our plan didn't work out, so it's back to the drawing board.

- A saying indicating that one's effort has failed, and one must start all over again:
“The new package we designed hasn't increased our sales as we'd hoped, so it's back to the drawing board.”

- If you go back to the drawing board, you have to start planning a piece of work again because the previous plan failed.
If the education reform is too expensive to implement, it's back to the drawing board for the committee.
Our proposal might not be accepted, in which case we'll have to go back to the drawing board.

ちなみに、「最初から」ということでは from scratch というイディオムもある。