In the US, the poor live quite comfortably. Even people with income of zero have consumption of about $20k/year.
For comparison, Hungary has a GDP per capita of $21k, the Czech Republic of $26k, France and the UK of $35k.
Further, inequality in the US is higher mainly because the rich earn more. That doesn't cause the life of the poor to suck, unless they get jealous or something.
Uh what? That individuals consume some amount of resources to live doesn't mean that they live comfortably. There is going to be some kind of minimum amount you have to pay to live, as you can't get everything for free even if you are homeless. That even those with the lowest incomes use up resources equivalent to $20k per year doesn't mean that those people are living comfortably, but we can see for Americans that there is some kind of minimum cost to living even if you can't make enough to pay for it all outright.
Drugs and poverty are intersectional. Laws for drug offenses involving substances most prevalent in poor communities have and continue to have harsher penalties than for drugs that are prevalent in more affluent communities. Drugs are highly available in poor communities, both for addicts and for those that want to sell them since economic advancement through traditional channels are denied to them. Police agencies in many cities enforce crime in the poorer parts of town that are inhabited primarily by people of color much more often than in more affluent areas.
The effects of drug prohibition amplify exiting social and economic issues in US society, so we know that US drug policy has been a total failure and must be changed.
If you want to argue that the lives of poor Americans suck, look at absolute consumption levels, or better yet, look at the actual basket of goods available to poor Americans.
Here is some data to get you started: http://www.census.gov/prod/2008pubs/h150-07.pdf
You may call it envy if that's how you see it -- if you indeed are interesting in learning about the many problems of economic inequality, I recommend the book The Spirit Level (http://www.equalitytrust.org.uk/resource/the-spirit-level).
I can think of no mechanism besides envy which would cause income inequality to harm anyone. It's not as if the US poor lack some good or service which is available in other, more equal societies.
Note that the Spirit Level only provides a correlation between inequality and other problems. It does not show the direction of causality.