the.com/third rail
the wire that powers your commute and ends arguments with 750 lethal volts
means A topic so dangerous or controversial that politicians and public figures avoid touching it, lest it destroy their careers; literally, the high-voltage rail that supplies power to electric trains.
from The literal sense comes from late-19th-century electric railways, where a 'third rail' running alongside the two running rails carries the current — touch it and the shock can kill. The figurative political sense is a 20th-century American coinage, often attached to debates over Social Security, captured in the warning that it's 'the third rail of politics — touch it and you die.'
- voltage
- Often 600 to 750 volts of pure direct current
- the metaphor
- Politics borrowed it: touch it, you're dead
- power source
- Carries the actual electricity, not the running rails
- deadly contact
- Stepping across tracks can complete a fatal circuit
- shoe pickup
- Trains drag a metal contact shoe along it