John Fund writes at National Review Online about the role document releases could play in deciding this year’s presidential election.

Of course, the presidential race is between Hillary Clinton and Donald Trump. But what if there’s another parallel race going on — a race to see how much scandalous material on both candidates will leak out before the election and who will be most damaged by it. Call it a contest between the IRS’s secrets (which Trump has reason to be nervous about) and Wikileaks (whose past leaks have already jolted Hillary’s campaign).

The past of both candidates might contain material that could tilt the direction of the presidential election. Donald Trump has steadfastly refused to release his tax returns despite early promises to do so and polls showing that 62 percent of Americans think it’s important for him to do. He has to worry about a potential leak of his IRS returns similar to the one Mitt Romney suffered in 2012.

In Hillary Clinton’s case, Wikileaks founder Julian Assange told the left-wing radio program Democracy Now in July that he has already released Hillary Clinton e-mails that “connect together with the cables that we have published of Hillary Clinton, creating a rich picture of how Hillary Clinton performs in office, but, more broadly, how the U.S. Department of State operates.” He has strongly hinted that further e-mails could shed light on the cozy relationship between State and the Clinton Foundation as well as on the State Department’s motivations for covering up details of the Benghazi terrorist attack in 2012.

Both sides are clearly nervous about possible revelations before the November election — or even before the first presidential debate on September 26. Donald Trump Jr., the candidate’s son, admitted to the Pittsburgh Tribune Review last week that the real reason for the non-release of the tax returns had to do with their political impact, rather than any ongoing IRS audit. Speaking to the paper’s editors, Trump Jr. said, “Because he’s got a 12,000-page tax return that would create . . . financial auditors out of every person in the country asking questions that would detract from [my father’s] main message.” In other words, the returns could reveal that his father’s wealth is substantially less than the $10 billion he claims, or that he makes fewer charitable contributions than he has stated, or that he takes advantages of tax loopholes and often pays zero or little in taxes.