From using tax data to track immigrants without legal status to threatening Harvard’s tax exemption, President Trump has been trying to use the IRS for his own political purposes in ways that seem unprecedented.

But they are not. Former President Richard Nixon laid the foundation forty years ago when he tried to use tax collectors to punish his enemies and assist his friends.

"One thing Nixon did consider is threatening the college's tax exemption," said Joseph Thorndike, director of the tax history program at Tax Analyst. "If you're reading the paper these days, it sounds familiar."

Nixon was angry that the university did not fight against the Vietnam War protesters. Trump also complained that Harvard and other Ivy League schools have not done more to protest against the Gaza War, a government crackdown on anti-Semitism on university campuses.

"We will take Harvard's tax-free status," Trump wrote in a social media post. "That's what they deserve!"

Despite the law enacted after Watergate, Trump is still on Nixon's old script to prevent the White House from interfering with such intervention.

Congress provides protection for the IRS

The 1971 Oval Office recording revealed how Nixon installed hand-picked executors at the IRS to conduct political bidding.

"I want to make sure he's a bitch-like son," Nixon told the assistant. "He'll do what he says. I know, every income tax return I want to see.

Thorndike said Nixon's plan to get involved in the tax returns program or to have the IRS investigate targets from its "enemy list" is not always successful.

But not because of the lack of attempts.

"Nexon tried very hard to abuse the IRS," Thorndike said. "Congress certainly sees it as a danger. If the president is developing an enemy and sending it to the IRS, essentially, it's worrying.

After Nixon left the office, Congress passed laws protecting the IRS and taxpayers from White House political interference. These laws are now being tested by the Trump administration.

Share tax information with institutions outside the IRS

For example, Congress passed a law to strictly limit who can access information taxpayers voluntarily provide to the IRS.

But last month, the tax collection agency reached an agreement to share some taxpayer data with immigration officials to help find and deport illegal people.

Immigration advocates are seeking court orders to prevent the IRS from sharing data with other government agencies.

In response to NPR's inquiries about the data sharing protocol, a Treasury spokesman defended the initiative as "decomposing data silos." But critics say the islands were placed there for some reason after the Nixon era.

"If the IRS is now forced to share data with people who shouldn't, it increases the risk of political goals," said Mike Kaercher, associate director of the NYU Center for Tax Law.

Shortly after the data sharing agreement was reached, the IRS's acting specialist resigned. Trump is now the fourth acting commissioner since taking office less than four months ago. His permanent work nominee, former Rep. Billy Long, R-Mo. Still waiting for a confirmation hearing.

Seeking to use IRS to target groups

Congress also attempted to prevent Nixon's enemy roster from replaying by banning the president and those around him from demanding or interfering with the IRS investigation.

“I used to work for the IRS,” Kahel said. “If you are an IRS person and you are on the receiving end of an inappropriate request for a political official to use the IRS as a weapon, then you should go to the Inspector General and report it immediately.”

That has not stopped Trump from insisting that the IRS should deprive Harvard and other nonprofits of tax-free status, which may require investigation.

Losing tax breaks would be a serious blow to Harvard, depending on tax-free gifts and their tax-free donations, which are nearly half of their annual budget.

"I think Harvard is a shame," Trump told reporters last month. "Tax-free status, I mean, it's a privilege. It's a privilege. It's a privilege. It's a abuse."

Although Nixon's plan for the IRS was secretly documented in the Oval Office, Trump launched his plan on social media and live TV.

"Donald Trump just said it out loud," Sandyk said. "Talking about the politicization of political institutions - I think I would say it was an option. I don't think it's a good option for the president."

Trump told reporters last month that he did not personally participate in the decision to revoke Harvard's tax exemption. But the leading Democratic senator called on the inspector general who oversees the IRS to investigate the president's actions.

The Inspector General did not respond to NPR's request for comment.

"There is even a question of whether the government violates these laws that prevent the weaponization of the IRS," Kaercher said.

The IRS is limited to tax enforcement

Meanwhile, the government called on the IRS to investigate individual targets, which also severely limited the agency's ability to pursue wealthy tax deception more generally.

According to the Inspector General’s report, the government has laid off more than 11,000 jobs at the IRS, including nearly one-third of tax auditors. More layoffs are expected in the coming months as part of a broad effort to narrow down the federal government.

This could hurt the federal budget, as every dollar spent on tax enforcement pays for itself in increasing tax revenue.

"It's in all our interests to operate, an effective IRS is in our interest," Thorndike said. "It just starved the staff organization and it really shocked the taxpayers immediately."