President Donald Trump ordered U.S. agencies on Tuesday to work closely with top adviser Elon Musk's effort to shrink the federal workforce by identifying government employees who can be laid off and functions that can be eliminated entirely.

With his 4-year-old son by his side or on his shoulders, billionaire Musk stood next to Trump in the Oval Office at the White House before the order was signed, taking questions from reporters and making it clear that he was leading efforts to cut what he saw as government waste at Trump's behest.

Wearing a "Make America Great Again" cap, the world's richest man defended his role as an unelected official who has been granted unprecedented authority by the president to dismantle parts of the U.S. government.

"You can't have an autonomous federal bureaucracy. You have to have one that's responsive to the people," Musk said. He called the bureaucracy an "unconstitutional" fourth branch of government that in a lot of ways had "more power than any elected representative."

Musk, the Tesla (TSLA.O), opens new tab CEO and owner of X, pushed back at criticism that he and his Department of Government Efficiency team have operated largely in secrecy.

DOGE has provided no information on whom it employs, where it is operating or what actions it is taking inside government agencies. It posts few actual results from its work, providing only dollar figures for purported cuts in specific agencies and little specific detail.

"I fully expect to be scrutinized and get, you know, a daily proctology exam, basically," Musk said. "It's not like I think I can get away with something."

Musk pushed back when asked about criticism from his detractors, including many Democrats, that he essentially has launched a non-transparent hostile takeover of government operations.

"You couldn't ask for a stronger mandate from ... the public," he said, citing Trump's election. "The people voted for major government reform. There should be no doubt about that."

Musk said he speaks to Trump, who sat at the Resolute Desk while Musk answered questions, nearly every day.

Tuesday's executive order was the latest effort by Trump and Musk to shrink and align the U.S. government with Trump's policy priorities. There have already been large-scale buyout offers, attempts to strip civil-service protections from federal workers and the effective shuttering of some federal agencies.

The order sets forth rules requiring government agencies to hire no more than one employee for every four workers who leave, and it compels agencies to work with Musk's team to identify large-scale reductions in force and determine which agency components may be eliminated outright.

The order exempts from cuts those employees whose work is critical to national security, public safety, law enforcement and immigration enforcement.

Many government workers belong to labor unions, which means any big layoffs or reductions in force must comply with their collective bargaining agreements. Nonunion employees of the civil service also enjoy job protections under federal law.

The push toward mass layoffs comes after the Trump administration attempted to cajole federal workers into accepting buyout offers. That effort has been blocked by a federal judge.

BUYOUT BLOWBACK

Musk and Trump said they expected to find some $1 trillion in savings through his efforts to identify fraud and waste in the government, a figure that would represent almost 15% of total federal spending.

Trump resisted the suggestion by Democrats and other critics that Musk's role presents a conflict of interest.

As CEO of rocket maker SpaceX, Musk oversees the company's contracts with the Pentagon and intelligence community that are worth billions of dollars.

"If we thought that, we would not let him do that segment or look in that area, if we thought there was a lack of transparency or a conflict of interest," Trump said.

Beyond blocking Trump's buyout plan, the courts have also paused his efforts to put U.S. Agency for International Development workers on leave and Musk's access to sensitive payment systems at the U.S. Treasury.

There are about 2.3 million U.S. civilian employees, excluding the Postal Service. Security-related agencies account for the bulk of the federal workforce, but hundreds of thousands of people work across the country in jobs overseeing veterans' healthcare, inspecting agriculture and paying the government's bills, among other jobs.

Earlier, Musk made a post on his social media platform X that harshly criticized firms that have filed lawsuits on behalf of federal employees.

"Which law firms are pushing these anti-democratic cases to impede the will of the people?" Musk wrote in the post.

Musk has also aimed his ire at judges who have issued rulings that paused Trump's executive actions. "Democracy in America is being destroyed by judicial coup," Musk wrote in a separate post on Tuesday.

Trump voiced a similar complaint during his meeting with Musk in the Oval Office.

"We want to weed out the corruption. And it seems hard to believe that a judge could say, we don't want you to do that," he said. "So maybe we have to look at the judges, because that's very serious. I think it's a very serious violation."

Trump said he would follow court orders.

"I always abide by the courts, and then I'll have to appeal it," Trump said. "Then what ... he's done is he’s slowed down the momentum, and it gives crooked people more time to cover up the books."