To keep doing something despite its apparent pointlessness or futility. There's no way he'll get his progressive agenda through—he's just beating the air.
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 ...
Meaning · fighting without any purpose. · going on with making futile attempts. · keep doing something, even though it is pointless. · make useless efforts.