© Adam Schultz/Biden for President
Former VP and presidential candidate Joe Biden
Joe Biden's tax proposals have gone through a variety of iterations over the course of his campaign, but lately, he's settled on a pledge not to raise taxes on those earning under $400,000. This pledge is not consistent with his current proposals, but he's even less likely to be constrained if he's elected president.

Even if Biden claims he would not directly raise income tax rates on those earning under $400,000, there are a number of policy changes he'd make that would directly or indirectly hit taxpayers under that threshold.

As one example, Biden has pledged to bring back Obamacare's individual mandate. Yet in 2018, the last year for which the penalties were still in place, nearly 3.7 million people earning less than $200,000 paid mandate taxes, according to IRS data, which represented nearly 99% of those who had to pay some sort of penalty. And 2.6 million, or about 69% of those who paid the mandate, earned less than $50,000.

Biden has also planned to overhaul the way tax breaks work for retirement savings. The Tax Foundation concluded that, on net, his "plan would reduce the tax benefit of traditional retirement accounts for those earning above $80,250 but under $400,000, violating Biden's tax pledge to not raise taxes on earners below the $400,000 threshold."

There are also indirect ways in which the Biden plan would hit those earning less than $400,000. For instance, increasing corporate income taxes, as Biden has pledged, would reduce the income of workers or shareholders of those companies.

While there's no doubt that, as proposed, Biden's taxes would hit the top 1% much harder, independent analyses from an ideological cross section of organizations (the Tax Policy Center, Penn Wharton Budget Model, Tax Foundation, and American Enterprise Institute) concluded that take home pay would be reduced at all income groups, even if just by a few hundred dollars for lower earners.

This, of course, is just what is being proposed. As Biden seeks funding sources for the massive new spending he's proposing, it will become increasingly difficult to confine tax hikes to those earning above $400,000.

One study from Moody's Analytics that is regularly cited by the Biden campaign found that his proposals would cost $7.3 trillion and raise $4.1 trillion in taxes. That leaves a gap of $3.2 trillion that would have to be filled in some way unless Biden just wants to pile money onto the national debt, which is already on track to smash the record set during World War II during his first term.

There is also less reason that Biden deserves the benefit of the doubt given his own history of breaking promises on taxes.

When he was Barack Obama's running mate in 2008, Biden pledged unequivocally, "No one making less than $250,000 under Barack Obama's plan will see one single penny of their tax raised, whether it's their capital gains tax, their income tax, investment tax, any tax." Yet, in addition to the mandate and other Obamacare taxes, Obama taxed cigarettes, which disproportionately hit those with lower incomes.

Given Democrats' increasing dependence on suburban voters, it's understandable that he would want to assure the middle class and upper-middle class that their taxes would not go up if he were president. But that's a promise that would quickly go up in smoke were he to win.