The I.R.S. audited the tax returns of both President Barack Obama and President Donald Trump after they took office.

The I.R.S. failed to audit Mr. Trump during his first two years in office despite a rule that states that the president and vice president are subject to mandatory review. It wasn't clear whether that lapse was indicative of general incompetence or whether Mr. Trump was treated differently.

The disclosure of the audits of Mr. Obama and Mr. Biden suggested that the agency was wrong to treat Mr. Trump unfairly.

The national taxpayer advocate from 2001 to 1969 said she was astounded. I think it is disturbing. You need to be auditing the president in the process.

The Ways and Means Committee obtained Mr. Trump's tax data last month after a yearslong legal battle.

The I.R.S. began auditing Mr. Trump's income after he left office. A large team of lawyers and accountants objected when the I.R.S. added two more people to help look at Mr. Trump's returns.

Concerns about potential politicization at the I.R.S. during the Trump administration are being raised by the discovery that the I.R.S. violated its rules. Questions have been raised about why the I.R.S. didn't devote more resources to auditing Mr. Trump.

The I.R.S. was run for most of last year by an acting head, David J. Kautter. The agency followed its rules, but not all of them.

Mr. Kautter and Mr. Rettig didn't reply to the request for comment. Mr. Koskinen only worked to make sure that Mr. Trump's tax returns were kept out of the public eye.

Mr. Koskinen said that it wouldn't have been appropriate to ask about the status of the examination.

The committee had little time to investigate, so it left many questions unanswered. Republicans will take control of the House in January and the Ways and Means Committee only received the information last month.

ImageMembers of the House Ways and Means Committee seated during a business meeting.
Representative Richard E. Neal, Democrat of Massachusetts, and the chairman of the Ways and Means Committee, had been seeking Mr. Trump’s tax records since 2019.Credit...Haiyun Jiang/The New York Times
Members of the House Ways and Means Committee seated during a business meeting.

The associates of several other former presidents did not respond to questions about whether or not they had been audited.

The chairman of the Senate Finance Committee, Ron Wyden, called the House panel's findings a "blockbuster" on Wednesday.

The presidential audit program is broken because the I.R.S. was asleep. There is no excuse for not conducting the required presidential audits.

The IRS has been the subject of controversy many times.

The New York Times reported that the I.R.S. had begun audits of two of Mr. Trump's enemies. Mr. Trump told his chief of staff that he wanted his rivals to face tax probes.

The inspector general found that both had been randomly selected for the initial pools from which the agency drew to carry out the exams. It's not clear how the I.R.S. made their final selections.

Mr. Trump told Senator McConnell, the majority leader, to prioritize a confirmation vote for a long time associate of his over the nomination of William P. Barr as attorney general. He worked with two of the Trump Organization's tax lawyers.

Mr. Trump appointed Mr. Rettig as commissioner after he defended Mr. Trump in a Forbes column.

"Teams of sophisticated tax advisers were likely engaged throughout Trump's career to assure the absence of any 'bombshell' within the returns." For the fact that they are the returns of Donald Trump, his returns are somewhat unremarkable.

Much has been said about the little glimpse of Mr. Trump's taxes. This month, the Trump Organization was found guilty of tax fraud. Mr. Trump and three of his children have been accused of overvaluing their assets.

ImageA view of Trump Tower.
The Trump Organization was convicted of a tax fraud scheme this month.Credit...Dave Sanders for The New York Times
A view of Trump Tower.

The Times gained access to years of his tax information and published a report in September 2020 that raised many questions about the legality of write-offs and deductions he had used to avoid paying taxes most years. The I.R.S. considered looking at Mr. Trump's tax returns after reading the article.

Republicans have tried to cut funding for the I.R.S. in the past. The report highlighted the agency's struggles in dealing with complicated tax returns filed by wealthy people, and criticized its willingness to trust returns filed by big accounting firms.

The I.R.S. is going to be overhauled in order to hire more specialists capable of auditing high-income taxpayers.

After a party-line vote, the committee obtained and made public any U.S. taxpayer's private information.

The committee released a report about Nixon's taxes after a scandal about whether he was under paying his taxes. The I.R.S. created a rule in 1977 to make it easier for agency officials to decide whether to audit their boss.

Republicans accused the I.R.S. of political discrimination because it used conservative terms when selecting groups to scrutinize for political activities that would make them ineligible to receive tax deductible donations. The inspector general found that the agency had used liberal terms for the same purpose.

The agency's commissioners are political appointees of the president. Mr. Koskinen ran the agency for a number of years that it audited Mr. Obama.

ImageCongressional aides wheeling a tranche of documents on a cart.
Congressional aides taking documents into the Ways and Means Committee’s business meeting on Tuesday.Credit...Haiyun Jiang/The New York Times
Congressional aides wheeling a tranche of documents on a cart.

Charles O. Rossotti, who was the I.R.S. commissioner from 1997 to 2002, said that he didn't play a role in the audit process.

Mr. Rossotti used a pole to keep away from that.

There is a requirement for presidential returns to be audited in the tax agency's internal review manual. According to the document accompanying the report, the exams were conducted by revenue agents.

According to the I.R.S., there are no reports of bias or partiality in the conduct of an officeholder's examination.

The lack of resources the I.R.S. devoted to auditing Mr. Trump's returns was documented in the report.

According to internal I.R.S. memos, it is not possible to get the resources available to examine all the issues raised in Mr. Trump's taxes.

It said that a larger team would be needed to do a thorough review of the returns.