There exists a phrase or device, somewhat akin to the parables of Paul Bunyan or John Henry, when your efforts at protest are futile against a struggle, but you are compelled to struggle against it anyways -- usually because it's a seemingly noble cause.
Would anyone have a suggestion as to how to phrase this device? Or is there a widely known idiom for it? I'd suppose the single word "futile" might accurately describe this situation, but that's not what I'm looking for.
Engage in conflict with an imagined opponent, pursue a vain goal, as in Trying to reform campaign financing in this legislature is tilting at windmills. This metaphoric expression alludes to the hero of Miguel de Cervantes' Don Quixote
Protests in which no immediate concessions are expected are sometimes described as symbolic. This sense of the word is defined by oxforddictionaries.com as "significant purely in terms of what is being represented or implied".
Flogging a dead horse (alternatively beating a dead horse, or beating a dead dog in some parts of the Anglophone world) is an idiom that means a particular request or line of conversation is already foreclosed or otherwise resolved, and any attempt to continue it is futile; or that to continue in any endeavour (physical, mental, etc.) is a waste of time as the outcome is already decided
In elections, you may "cast a protest vote" for a candidate who you know won't win, but whose vote total you want to increase. This helps show support for the candidate's message or ideas. Or, it helps show public dissatisfaction with the other candidate, even if that candidate wins the election anyway.
In other contexts, you may do or say something
"just to make a point" or "just to make a statement."
Also, beat the wind. Continue to make futile attempts, fight to no purpose. For example, The candidates for office were so much alike that we thought our vote amounted to beating the air . These phrases call up a vivid image of someone flailing away at nothing. [Late 1300s]
The American Heritage® Dictionary of Idioms
Several people are associated with this proverbial saying, notably
John F. Kennedy. It was brought to the public's attention by Peter
Benenson, the English lawyer and founder of Amnesty International, at
a Human Rights Day ceremony on 10th December 1961. The candle circled
by barbed wire has since become the society's emblem
I like this because it is hopeful. Causes are not lost until everyone stops fighting for them. It can be a long time before the cause is won, but "Progress happens one funeral at a time" is overly pessimistic. I think.