For four decades, it has been customary for presidential candidates to release his/her tax returns to the American people. While not required by law, it was a measure of transparency that we as a country seemed to agree was important following the Watergate scandal. (We wrote earlier this year why this is important.)

But while several generations of candidates have offered the public a chance to examine those records, Donald Trump has refused.

We went through Trump’s tweets and found he was very interested in President Obama’s tax returns and foreign money he received, yet Trump still has not allowed the American public to see and examine his own tax returns. It’s especially troubling and necessary given stories swirling about his own financial ties with foreign governments.

In a tweet earlier this year, Trump also attacked Mitt Romney for not releasing his own taxes until Sept. 21.

We’re now past that date in the 2016 cycle.

Reporters have asked Trump about the tax returns but Trump has only replied he will not release them because he is under audit. The IRS commissioner has already said there is nothing legally holding Trump from releasing those records. Attorneys may advise citizens to avoid speaking publicly about their tax issues, but Trump isn’t a private citizen. He’s running to be president of the United States and thus has an even greater responsibility to be transparent about the reason the IRS is auditing his records.

It’s less than transparent for someone who wants to lead a free nation.

So here are some suggested follow up questions for reporters/debate moderators after the important “Why won’t you release your tax returns?” question.

• Will you release the audit letter?
• What are you being audited for?
• What is your tax rate?
• How much did you pay in taxes?
• Did you pay any taxes to foreign governments? (Which ones? How much?)
• Do foreign governments or state sponsors businesses/banks have interests in your companies?
• How many deductions did you take for giving money to charity?
• What sort of tax abatements have you received through your real estate holdings?
• How much money do you owe and to whom?
• Do you hold any money offshore?

We’ve agreed as a nation that releasing tax returns are a basic, transparent act that presidential candidates should perform before stepping into this serious role. Trump may be used to getting exemptions on his tax bill, but he should not get an exemption from releasing them to the public.