This is a genuinely contested policy question involving competing values (fairness, growth, revenue needs) rather than a factual matter with a settled answer, so I can't tell you definitively what "should" happen. But I can lay out the substantive arguments on each side so you can weigh them yourself.
Arguments for raising taxes on the wealthy
•Ability to pay / diminishing marginal utility: A dollar taxed from a billionaire causes less sacrifice than a dollar taxed from a middle-income worker, so higher rates on the wealthy are seen as more equitable.
•Rising inequality: Wealth and income concentration at the top has grown substantially in the U.S. over recent decades, which some argue justifies more progressive taxation to fund public goods and reduce disparities.
•Effective tax rates vs. statutory rates: Because of capital gains treatment, deductions, and tax planning, many wealthy individuals pay effective rates lower than their statutory bracket—and in some analyses, lower than middle-class earners when payroll taxes are included. This is a common argument for reform (e.g., taxing capital gains like ordinary income, closing loopholes, or a wealth tax).
•Revenue needs: Higher rates on top earners could fund deficits, social programs, or infrastructure without raising taxes on lower earners.
•Historical precedent: Top marginal U.S. tax rates were much higher in the mid-20th century (over 90% briefly in the 1950s-60s) without preventing strong economic growth, suggesting room to raise rates isn't necessarily catastrophic.
Arguments against raising taxes on the wealthy
•Incentives and growth: Higher marginal rates on income, capital, and investment can reduce incentives to work, save, invest, or start businesses, potentially slowing economic growth.
•Capital mobility: Wealthy individuals and capital are mobile; very high rates could drive relocation of people, businesses, or investment to lower-tax jurisdictions.
•Already progressive system: Critics note the top earners already pay a large share of total income tax revenue, and argue the system is sufficiently progressive.
•Behavioral responses: Historically, when top rates were very high, effective rates paid were often much lower due to extensive loopholes and avoidance, so statutory rate comparisons across eras can be misleading.
•Alternative approaches: Some argue better enforcement, closing loopholes, or consumption-based taxes are more efficient than raising marginal rates.
Where the disagreement really lives
Much of the debate hinges on empirical questions that are themselves disputed—like how sensitive investment and work behavior actually are to tax rates, what counts as "wealthy," and whether wealth taxes (as opposed to income taxes) are administrable. It also hinges on value judgments about fairness, the proper size of government, and how much redistribution is desirable—these aren't questions with an objectively correct answer.
If you want, I can dig into specific proposals (e.g., wealth taxes, capital gains reform, the "Buffett Rule," or comparisons to other countries) or look at what economists across the political spectrum currently say about growth effects.