Here’s the funny thing: Biden’s 8 percent estimate is derived from that same tax data on the top 400 taxpayers. So what’s going on? The president is describing a tax system that he wishes existed — not the system in place.

As Kessler noted, under the 16th Amendment of the Constitution, ratified in 1913, “Congress shall have power to lay and collect taxes on income, from whatever source derived.” //

Biden and the Democrats dishonestly use a definition of income, to Kessler's previous point, that they wish existed, vs. the definition that does exist, per federal tax legislation and the IRS. //

Note that unrealized capital appreciation is not included in the above definition of income. //

Here's more from Kessler:

In 2021, two White House economists — Greg Leiserson of the Council of Economic Advisers and Danny Yagan of the Office of Management and Budget — published a blog post that estimated what the tax rate would be for the 400 wealthiest households if unrealized capital gains were considered part of income. ... The report estimated that these households had an average federal individual income tax rate of 8.2 percent for the 2010-2018 period.

The steep run-up in stock prices in recent years has meant the wealth of super-wealthy Americans has risen significantly, even if they never sell stock that would trigger a tax liability. In fact, when interest rates were low, it was more cost-effective for a billionaire to borrow money against the value of those shares than sell them. The White House economists estimated what the tax rate would be if that income — now not subject to taxation — were included on their tax returns.