slender reed

Some source of support that proves to be extremely limited, weak, or unreliable. For all his boastful talk, he ended up being little more than a slender reed when the situation became challenging. The idea that voters' opinions will shift enough between now and election day is but a slender reed of hope that her campaign is clinging to at the moment. It was on this slender reed of evidence that the prosecution built their entire case.

slender reed, a

A weak and unreliable support. This metaphor dates from biblical times, appearing in both Old and New Testaments. In the former, in the books of Isaiah and 2 Kings, it was applied to Egypt, which was variously described as a “broken” or “bruised” reed, not to be trusted if the Assyrians made war on the Hebrews. The term persisted into the mid-twentieth century but is heard less often today.