Republican presidential nominee Donald Trump has refused to release his tax returns, making him the first major-party nominee since Richard Nixon in 1972 not to do so. Three bills introduced in Congress, mostly by Democrats, would require both the major-party nominees for president from now on to release their tax returns. All three bills — H.R. 5386, S. 2979, and S. 3348 — are titled the Presidential Tax Transparency Act

The context

Although Trump has claimed his returns are currently under audit and so cannot be made public (though the IRS said an audit did not prevent Trump from releasing his returns anyway), many speculate that Trump may be withholding the information because he pays little to no federal income taxes — as leaked pages from his tax returns the New York Times published seemingly indicated. Some also speculate, with little evidence, that Trump may have business dealings with Russia or, more likely, that he doesn’t donate nearly as much money to charity as he claims, which could be revealed or dispelled by his tax returns.

Although it’s not a law for presidential candidates to release this information, for several decades it’s been something of a de facto expectation. During this election cycle, Hillary Clinton, Tim Kaine, Mike Pence, Bernie Sanders, Ted Cruz, John Kasich, and Marco Rubio all voluntarily released their tax returns. In other recent election cycles, Barack Obama, Joe Biden, Mitt Romney, Paul Ryan, John McCain, and Sarah Palin all did too.

The candidates all chose to do this even though the information could at times be politically embarrassing, such as Clinton’s sky-high fees she charged for speeches to Wall Street banks, which many critics, even within her own party, attacked her for.

What the bills do

The legislation would require both major-party presidential nominees to release their tax returns for the previous three years within 15 days of receiving their party’s nomination. If a nominee does not comply, then the legislation allows the Federal Election Commission (FEC) to request the Department of the Treasury to release the returns, bypassing the candidates themselves.

A “major-party nominee” is defined as a party whose candidate received at least 25 percent of the popular vote in the previous presidential election, which in practice would mean the Democrats and Republicans. (The best third-party showing in the past few decades was Ross Perot in 1992 with 18.9 percent of the vote, and the best-performing third-party candidate this time is the Libertarian Party’s Gary Johnson who polls indicate is unlikely to reach even 10 percent.)

H.R. 5386 was introduced by Rep. Anna Eshoo (D-CA18), while S. 2979 and S. 3348 were both introduced by Sen. Ron Wyden (D-OR).

What supporters say

Supporters argue that the bills provide much-needed transparency and codifies a longstanding practice into law.

“The American people justifiably have the expectation that those who are the nominees for the highest office in the land should be open and transparent about their tax returns,” House lead sponsor Eshoo said in a press release. “Tax returns are highly instructive. They contain vital information, such as did the person pay any taxes; did the person make charitable contributions; did the person take advantage of tax loopholes; or did the person keep money offshore.”

What opponents say

Opponents counter that the bills aren’t really the transparency measure that they’re pretending to be, but rather a partisan measure advanced by Democrats meant to embarrass Trump.

“While tax returns can answer those questions, it would be misguided to mandate their disclosure. As the law stands, candidates must disclose voluntarily, which provides voters with a valuable signal,” Joshua Blank, faculty director of the graduate tax program at the New York University School of Law, wrote in a Wall Street Journal op-ed. “If every applicant for the law firm position were legally required to wear a business suit to the interview, the partners could no longer easily weed out the people who otherwise would have showed up in a T-shirt.”

Odds of passage

The House bill has attracted 33 cosponsors: 31 Democrats and two Republicans, Rep. Walter Jones (R-NC3) and Rep. Mark Sanford (R-SC1). It has not yet received a vote in the House Ways and Means or House Administration Committees. S. 2979 and S. 3348 have attracted nine cosponsors and eight cosponsors, respectively, and all Democrats.

One of the Democratic cosponsors of both Senate bills is Sen. Tim Kaine (D-VA), the Democratic vice-presidential nominee who released his own tax returns after being named as the running mate. Kaine signed on as a cosponsor on June 7, 2016, about a month and a half before he was officially named as the running mate, although even by early June he was considered a leading frontrunner for the spot.

As Election Day approaches in a few days, GovTrack Insider this week is running a series spotlighting bills introduced in Congress that deal with elections and campaigns.

This article was written by GovTrack Insider staff writer Jesse Rifkin.