How can Joe Biden claim to defend Obamacare—let alone Medicare—when he created a tax strategy specifically to avoid paying taxes that fund those two programs?

In the campaign for the 2020 Democratic presidential nomination, Joe Biden has portrayed himself as Obamacare’s biggest defender. His health care plan, released this month, pledges to “protect the Affordable Care Act” and states that he “opposes every effort to get rid of this historic law.”

However, his campaign rhetoric in support of Obamacare overlooks one key fact: For the past two years, Joe Biden structured his financial dealings specifically to avoid paying a tax that funds “this historic law,” along with the Medicare program.

When Biden released his tax returns from 2016 through 2018 earlier this month, the Wall Street Journal analyzed those returns and found that the former vice president and his wife Jill funneled most of his book and speech income through two S corporations. The corporations gave the Bidens more than $13 million in total profits, while distributing less than $800,000 to them as salary.

While the Bidens paid federal income taxes on all their income, they did not have to pay self-employment taxes on these millions of dollars in profits. The Bidens saved as much as $500,000 in self-employment taxes by taking most of their compensation as profits from the corporation, as opposed to salary.

The Journal cited multiple tax experts who called the Bidens’ move “pretty aggressive,” and a “pretty cut and dried” abuse of the system. Given that most of their income came from writing and speaking engagements, one expert called that income “all attributable to [their] efforts” as individuals and thus wage income, rather than a broader effort by any corporation resulting in profits.

Most important to Biden’s political future is what that foregone self-employment tax revenue would have funded. Section 9015 of Obamacare increased the tax’s rate from 2.9 percent to 3.8 percent for all income above $200,000 for an individual, and $250,000 for a family. By taking comparatively small salaries from their S corporations and receiving most of their income as profits from those corporations, the Bidens avoided paying a tax that funds an Obamacare law Joe Biden claims he wants to defend.

Moreover, the other 2.9 percent in self-employment tax helps finance the Medicare program, which faces its own bleak fiscal future. According to the program trustees, the program will become insolvent by 2026, just seven years from now. If people like Joe Biden use tax strategies to avoid paying self-employment taxes, Medicare’s date of insolvency will only accelerate.

During the last presidential election cycle, Sen. Bernie Sanders repeatedly returned to Hillary Clinton’s paid speeches before companies like Goldman Sachs. Both the more than $100 million in income Bill and Hillary Clinton generated from their speeches, and Hillary Clinton’s insouciance at the vast sums she received—“That’s what they offered,” she said of the $675,000 sum Goldman Sachs paid her to give three speeches—made her look out-of-touch with the concerns of families struggling to make ends meet.

Likewise, Biden’s 2020 competitors almost certainly will use the questions about his taxes to undermine his image as “Middle Class Joe.” Few middle-class families will make in a lifetime the $15.6 million in income that the Bidens received in but two years. Moreover, how can Joe Biden claim to defend Obamacare—let alone Medicare—when he created a tax strategy specifically to avoid paying taxes that fund those two programs?

In 2014, Barack Obama, whose administration proposed ending the loophole the Bidens used to avoid self-employment taxes, attacked corporations for seeking to migrate to lower-tax jurisdictions overseas: “It is true that there are a lot of things that are legal that probably aren’t the right thing to do by the country.” In Joe Biden’s case, his tax behavior probably wasn’t the right thing to help his political future either.