All societies include an underclass, but ours generally encompasses subgroups such as the mentally, or physically impaired, which we do strive to take care of, especially by the good works of the private sector, the young adult, the elderly, the new immigrant, etc. With the exception of the elderly, who should have taken care of themselves in their life, but who we also strive to provide for, all eventually experience upward mobility and enjoy the ability to raise themselves from your "underclass." The difference between us and much of the rest of the world is that we allow that mobility, the low may rise, the high can fall, and we do not condemn a person born into a class to remain in that class. In short, if you have any sort of ambition, then you will better yourself in our system. If you have no ambition, you are not a victim of the system, you're just lazy and content to be in an "underclass." We have all known people like that in our lives.
I see "undercass" as in a caste system, second rate citizens without or with fewer rights.
We don't have one of those despite the lefts best attempts to make it sounds as though we do...ya know, because gotta smear the USA at every opportunity. That's how "progressive" 'patriots' show their love of country.
We just have poor people. That's not an underclass, they are just poor.
Communism won't fix that no matter how much the "progressives" stamp their feetsies that it will.