Science has shown that the more money you have, the more you lose empathy for others. Maybe start there.

I'd say it could be a way to do that technically. Counting on laws to take a measure that would appear as "objective" will reduce the benefits, because some will try and manage to circumvent the law, not appear as rich etc. And who makes law right now anyway ?

The more direct approach is to say "no more someone can own such an amount of things, thereby now the society will own everything human made and its benefits evenly shared. We start by taking back from the richest that profitted off people's work."

This way, it's easy to understand and bears little flaw, it's easier to defend too because you can sum it up with just "equality". The rich can live the same life as everyone else.

I know USA is far from being close to decide that, and that is part of for reasons the rich fight for.

You're probably welcome to portray them that way, but given the number of rich arseholes in most powerful governments and the amount of money flowing from other rich arseholes into those governments, taking the means of production back is probably still going to require some aggressive action.