Instead of just trying to tax the rich more, it would be better to prevent the distribution of income from being so unjust to begin with. Markets have been rigged in numerous ways to redistribute income upward to the wealthiest members of society.
Given the enormous increase in inequality over the last four decades, and the reduction in the progressivity of the tax code, it is reasonable to put forward plans to make the system more progressive. But, the bigger source of the rise in inequality has been a growth in the inequality of before-tax income, not the reduction in high–end tax rates. This suggests that it may be best to look at the factors that have led to the rise in inequality in market incomes, rather than just using progressive taxes to take back some of the gains of the very rich.
There have been many changes in rules and institutional structures that have allowed the rich to get so much richer. (This is the topic of the free book Rigged.) Just to take the most obvious — government-granted patent and copyright monopolies have been made longer and stronger over the last four decades. Many items that were not even patentable 40 years ago, such as life forms and business methods, now bring in tens or hundreds of billions of dollars to their owners.
If the importance of these monopolies for inequality is not clear, ask yourself how rich Bill Gates would be if there were no patents or copyrights on Microsoft software. (Anyone could copy Windows into a computer and not pay him a penny.) Many other billionaires get their fortune from copyrights in software and entertainment or patents in pharmaceuticals, medical equipment and other areas.
The government also has rules for corporate governance that allow CEOs to rip off the companies for which they work. CEO pay typically runs close to $20 million a year, even as returns to shareholders lag. It would be hard to argue that today’s CEOs, who get 200 to 300 times the pay of ordinary workers, are doing a better job for their companies than CEOs in the 1960s and 1970s who only got 20 to 30 times the pay of ordinary workers.
Another source of inequality is the financial sector. The government has aided these fortunes in many ways, most obviously with the bailout of the big banks a decade ago. It also has deliberately structured the industry in ways that facilitate massive fortunes in financial engineering.
There is no reason to design an economy in such a way as to ensure that most of the gains from growth flow upward. Unfortunately, that has largely been the direction of policy over the last four decades.