First of all, we should note that very few people, if any, would admit to believing in Social Darwinism today. It is an idea that has a very bad reputation. Therefore, even people who believe in many of its tenets would not call themselves Social Darwinists. That said, people still do believe very much in the idea of the deserving and the undeserving poor in the United States today.
The deserving poor are typically defined as those who work hard, do not commit crimes or use drugs, who generally behave well, but are simply still poor. This may be because they were not able to get much education when they were young, for example. So, they lead exemplary lives and therefore “deserve” to be better off than they are.
The undeserving poor are those who do not fit this pattern. They may be women who had children when they were teens. They may be people who have drug problems. They are, it is believed, out of work because they are too lazy to get and keep work.
We can see the idea of the difference between the deserving and the undeserving in the push for things like drug tests for people on welfare. This stems from the idea that only the deserving poor are worthy of public help.