Yes I think it works if enough people do it. Then the Congressfucks get worried and decide whether the cause du jour is really worth sticking their necks out for.
My representative is Chinese-spy-fucking Eric fucking Swalwell who literally threatened to nuke his own constituency. Do you really think gives a flying fuck about anything I'd write to him?
All I ever get back is a form letter, stating the reps view. Basically FU unless you're in agreement.
I just send a brief opinion against vaccine mandates, not expecting much...