Why do we say "A rising tide lifts all boats"?

Background:

A phrase used mainly by politicians and economists that refers to the macro-economic theory that improvements in the general economy will benefit all participants in that economy.

It was popularized by John F. Kennedy and is often attributed to him. However, as Kennedy's speechwriter Ted Sorensen, reveals in his memoir, he came across the phrase during his first year working for Kennedy, when JFK was a senator. While researching New England's economic problems, Sorensen observed that "the regional chamber of commerce, the New England Council, had a thoughtful slogan: 'A rising tide lifts all the boats.'"

Kennedy used the phrase frequently from then on. In recent years it has tended to be used to defend policies that benefit high income earners.

More expressions and their source

Challenge yourself with BookBrowse Wordplays