Trump demanded VP candidate tax docs he won't make public

In a Thursday talk delivered through Facebook, Trump vice president finalist Newt Gingrich said the campaign required him to submit more than one decade's worth of tax returns as part of the vetting process.

In a 2012 editorial, the lawyer picked by Trump's campaign to help with vetting described the review of tax returns as a cornerstone component of the vice presidential selection process.

"Trump clearly wanted to see the tax returns to see if there's a problem there," said Joseph Thorndike, a tax historian and contributing editor to Tax Analysts, an accounting trade publication.