in the soup

"in the soup"という表現をご存知でしょうか？

苦境に陥る、困ったことになる、という意味で使われます。


As a Presidential candidate, Donald Trump led a charmed existence. Whatever he said, no matter how outrageous, it didn’t seem to hurt him.

（中略）

Now things have changed. He might never admit it, but Trump has belatedly discovered a basic principle of politics: words matter. They matter so much, in fact, that they can make or break a Presidency.

（中略）

What can’t be denied is that, yet again, the White House is in the soup. The President and his aides now know that words and truth do matter. Yet they continue to act as if they are oblivious. At a press conference with Angela Merkel, the German Chancellor, on Friday afternoon, a German reporter asked Trump, “Why do you keep saying things you know are not true?” Trump didn’t answer directly. When another German reporter asked Trump about the White House citing claims that the British government bugged him, he refused to take responsibility. “We said nothing,” he said. “All we did was quote a certain very talented legal mind who was the one responsible for saying that on television. I didn’t make an opinion on it.” And, once again, Trump refused to back off the discredited claim that Obama bugged him. Looking at Merkel, whose phone the N.S.A. reportedly tapped for years, he said, jokingly, “At least we have something in common, perhaps.”
(John Cassidy. Donald Trump Finally Pays a Price for His False and Reckless Words. The New Yorker. March 17, 2017.)


ちょっと引用が長くなってしまいましたが、大統領選の時から放言、暴言を繰り返してきたトランプ氏も、大統領に就任してからはやはりその発言の重さというものに縛られざるを得ない状況であろうというのが記事の内容です。

特に、大統領選期間中にオバマ元大統領がトランプ氏を盗聴していたという一方的な主張は、結局のところ根拠の無い中傷らしいことが明らかとなり、ホワイトハウスは「苦境に立たされて」（in the soup）いるというものです。

手元にあるCollins Cobuild Dictionary of Idiomsにも"in the soup"が載っています。

気になるのは、何故"in the soup"が「トラブル」を意味するようになったのかということですが、色々当たってみたのですがどうも判然としません。