put one’s thumb on - 常時英心：言葉の森から 1.0

米民主党全国大会に際し, 不正疑惑が浮上していたことを受け, デビー・ワッサーマンシュルツ委員長は辞任する意向を表明しました。

Wasserman Schultz to Step Down as Democratic National Committee Chair

On the eve of the 2016 Democratic National Convention, Debbie Wasserman Schultz announced she would resign as Democratic National Committee chair at the end of the convention.

In a statement laying out the goals of this election cycle she wrote: "The best way for me to accomplish those goals is to step down as Party Chair at the end of this convention. As Party Chair, this week I will open and close the Convention and I will address our delegates about the stakes involved in this election not only for Democrats, but for all Americans."

Her announcement comes amid the release of internal DNC emails by Wikileaks that appear to show the inner workings of the Democratic Party and what seems to be party officials attempting to aid the Hillary Clinton campaign during the primaries.

中略

During the primary battle, Sanders and his supporters accused both the party and Wasserman Schultz of putting their thumb on the scale for Clinton and these emails may indicate support for those allegations. Sanders called for Wasserman Schultz to step down.

以下省略

http://abcnews.go.com/Politics/wasserman-schultz-step-democratic-national-committee-chair/story?id=40838011

本日気になった表現は “putting their thumb on” です。

『リーダーズ英和中辞典』(研究社)で調べると, “put [lay] one’s [a] finger on” で「<問題点・原因など>をはっきりと指摘する」とありました。

Oxford-Dictionaries.comには “identify something exactly” と定義され, “He cannot put his finger on what has gone wrong.” という例が挙げられています。

今回の表現に “finger” を用いた場合と, “thumb” を用いた場合の違いが気になり, 上記の辞典で他の熟語表現を確認したところ, どちらも同義を示すということがわかりました。(Cayu)