Of the two, the decline of the middle class is far more worrisome to me. No doubt there are plenty of causes, chief among them free trade, which has exposed formerly protected union jobs to low wage asian competition. I understand the concept that the country is supposed to be better off as a whole from this, but I have my doubts. Other countries certainly seem to do everything possible to preserve high paying manufacturing jobs, while we seem quite content to see them go overseas.
I am extremely suspicious of government getting involved in trying to equalize wealth distribution, for all the obvious reasons. One exception I would make is executive compensation, which has clearly gotten out of control and constitutes a market failure that justifies government regulation. If the government can tell companies what percentages of various races to hire, tell them whether or not their employees can smoke in their own offices and instruct them on relations between its male and female employees, then it can certainly restrict obscenely excessive options and bonus packages. If such compensation is required, let the company pay it with cash money so the accounting is accurate and not steal it from the shareholders with disguised compensation.