It's a common headline: a billionaire public petitions for higher taxes on the ultra-rich. Yet, you rarely see those same individuals cutting voluntary checks to the U.S. Treasury . That's because the American tax system isn't built for donations, but rather for taxable income , deductions, and incentives. So, even if a high-net-worth person sent money to the federal government, that extra cash would simply go toward the nation's $39 trillion national debt — without changing the donor's tax liability. This disconnect is key since it helps explain a broader frustration with the IRS tax code. From just $107.88 $24.99 for Kiplinger Personal Finance Become a smarter, better informed investor. Subscribe from just $107.88 $24.99, plus get up to 4 Special Issues CLICK FOR FREE ISSUE Sign up for Kiplinger’s Free Newsletters Profit and prosper with the best of expert advice on investing, taxes, retirement, personal finance and more - straight to your e-mail.…