President-elect Donald Trump’s decision to bring his children into his inner circle, alongside far-right adviser Stephen Bannon, has provoked concerns about nepotism, ethics and national security, and experts worry he will go unchecked in office.

Trump can easily ignore calls to act otherwise, experts say, and critics will have few options even after he assumes the Oval Office.

On Thursday, his transition team handed out official photographs showing Trump with Japanese prime minister Shinzo Abe, in the gilded rooms and hallways at Trump Tower in New York. His elder daughter, Ivanka, and her husband Jared Kushner were in tow, neither of whom have national government security clearance. The photo coincided with news that Kushner has sought legal advice on whether he could join the Trump administration, a move that could violate federal anti-nepotism law and risk legal challenges and political backlash, according to the New York Times.

The president-elect has kept his two adult sons, Donald Jr and Eric, close to his transition team as well. He has insisted that, after inauguration, he will let his children run his business interests while he attends to the duties of commander in chief.

Bannon, a former Goldman Sachs executive and CEO of the far-right, conspiratorial Breitbart News, was only the first of several highly controversial cabinet appointments. On Friday Trump nominated Senator Jeff Sessions to be attorney general, and the retired general Mike Flynn to be national security adviser, leaving progressives and ethics watchers reeling.

Norman Eisen, a former special counsel and ethics adviser to Barack Obama, accused Trump of acting “like something out of a tin-pot oligarchy”. Writing in Fortune, he said “this is not the way we behave” in America.

But there is no evidence that Trump intends to heed such criticism, nor that he could have to confront it legally.

“The key is, he is smashing norms and making his own, but that does not mean he is violating the law in any way,” Robert Rizzi, a government compliance and ethics lawyer in Washington and a visiting professor at Harvard Law School, told the Guardian.

This may not even change much once Trump holds the Oval Office. His family, however, will have to tread cautiously. A federal nepotism law, enacted after President John F Kennedy made his brother, Robert, attorney general, prevents a public official from appointing a relative “to a civilian position in the agency in which he is serving or over which he exercises jurisdiction or control”.

But as long as Kushner and the Trump children are not federal employees, whether paid or unpaid, but are simply “hanging around the White House a lot”, one ethics expert said, they may dance around the law. The expert, who asked not to be named because of current representation for government figures, said that if Trump’s children and son-in-law continued talking to Trump without giving any administration staffers instructions, then it would be difficult to find a law that they had violated.

Hillary Clinton took a formal role in Bill Clinton’s White House to try to achieve healthcare reform, but she had an official position, first lady of the United States. She was able to proceed unimpeded legally, although her efforts failed and she suffered enormous political fallout after the project.

Ethics watchdogs may still try to sue Trump if they can find conflicts of interests with his business, apparent nepotism for his children, or efforts to promote his or his children’s brands from the presidential podium.

There are many loopholes, however. Kushner, with the ear of the president, can define himself merely as a consultant or an informal adviser – a “wise man” in the style of unofficial senior advisers who had the ear of Lyndon Johnson in the Vietnam war era.

Though Trump has defied protocol in the limbo before his inauguration – holding court in a skyscraper, shutting down central Manhattan – his deviations may be shocking, and nothing more.

“President-elect Trump is still a private citizen, and it would seem to me that the prime minister of Japan met with a private citizen and a variety of other citizens,” said Ryan Meade, law professor at Loyola University and director of the center for compliance studies. “He is not a government official yet, he can’t rep the United States. He certainly could discuss where his policy would go in future, but he cannot bind the US in any way.”

Ivanka Trump with her husband Jared Kushner at Trump Tower on 18 November. Photograph: Mike Segar/Reuters

Meade compared the meeting to Trump’s visit with Enrique Peña Nieto, the president of Mexico, during the campaign. “His legal status has not changed. It’s an informal meeting, trying to build a personal relationship, and it’s not technically troubling that there were people in that meeting or the meeting with Abe who did not have security clearance,” Meade added.

Once Trump is president, Meade said, he and the people around him will need security clearances to meet foreign heads of state.

The expert who requested anonymity noted that Trump has also, apparently, refused assistance from state or defense department officials, who normally start to advise a president-elect. The rebuff would ruffle feathers in Washington, but not in much of the US.

“The public does not care. They voted for change,” the expert said.

Tradition dictates, too, that the president-elect first call the prime minister of Britain after winning the election. Trump did not know or care. He spoke to many leaders, including Vladimir Putin of Russia, Benjamin Netanyahu of Israel and others, before finally having what appeared to be a casual conversation with Theresa May.

“It all looks terrible,” the expert said. “His whole transition is a train wreck. Some things will be different when he is in power, but not to the extent some people might expect or like. Don’t conflate norms with what is legal or illegal.”