You can make easily a tin star by cutting that feeble metal from, for example, a fruit can. To carry it is more difficult. From outside the USA it seems public workers aren't so valued as private entrepreneurs.
But not all people serve to do business privately, and some have to choose public work. One of these tasks is being sheriff in old west. In this movie the figure of the sheriff as a public server is well seen: a man not very capable as I suppose were almost all, elected between the people of a small village, honest but without real skills to impose the law against dangerous bandits: So then, that famous tin star should weigh terribly. In contrast there is the gunman: he's very able with firearms but in this film shooting exhibitions pass to a secondary plane. The personage played by Henry Fonda basically knows his profession in full and furthermore, it remains in a slight dark the feeling that he doesn't value life too much, nor those of his preys nor his own, as he's a bitter, lonely, disillusioned man of and uncertain age with not much to lose. That quality, paradoxically, gives him an advantage in all fights owing to a quiet, indifferent mood the sheriff can't attain as he wants to live and hates troubles. The sheriff must risk against his will; the gunman afford these risks without much worry and all these isn't only a matter of mastery with the revolver. The two protagonists are very well chosen, contrasting the sober Fonda with the disquiet Perkins, but in the film at the end, the two men have changed.