How can I apply John Rawls theory of justice to everyday decision making?
By remembering: "There but for fortune go you or I".
I've argued elsewhere that the appeal of Rawls' theory comes from it being an example of intersubjectivity, which undergirds conceptual communication and abstract reasoning, following the Private Language Argument. Discussed here: According to the major theories of concepts, where do meanings come from?
So whenever we generalise a subjective dilemma about justice rather than essentialise, we are using reasoning that corresponds with Rawls'.
Contrast this to for instance racial reasoning, like the idea only some people are noble and that is determined by heritage and somehow inescapable. This was a popular approach until very recent times, with justice around disputes & crimes determined by jarls & other nobles. The UK House Of Lords is still our highest court of appeal.
Phrases like 'The blood will out' and 'The apple doesn't fall far from the tree', show us how people thought. Universal education and other measures to make society fairer and more just, have provided endless examples to disprove these ideas, so that we see them as backwards and indefensible. But that shouldn't make us lose sight of how recent a shift it is, or the importance of that essentialising thinking as an atavism in politics.
In US politics dog-whistles about violence and crime by 'inner city people' is increasingly becoming overt condemnation of Mexicans and any (dark skinned) immigrants. Marjorie Taylor Green just called for a caucus around 'Anglo-Saxon values', very reminiscent of a Kipling-esque picture of 'The white mans burden'.
It's not just about racism. Whether we consider people capable of reform or redemption also comes into whether we allow empathy and intersubjectivity, or essentialise others as having fixed qualities fundamentally different to our own.