The political potential of Donald Trump was first noticed by a prominent member of a presidential family. On December 21, 1987, Richard M Nixon wrote to Trump in the following glowing terms:

“Dear Donald, I did not see the program but Mrs Nixon told me that you were great on The Donahue Show. As you can imagine, she is an expert on politics and she predicts that whenever you decide to run for office you will be a winner! With warm regards, Sincerely, RMN.”

Even in retirement, Pat Nixon continued to exercise a primary influence over her husband’s political assessments. This is far from unique in US presidential politics, as best illustrated by Lyndon Johnson asking Lady Bird for her judgment immediately at the conclusion of a presidential address. On the phone to the White House family quarters, the President would ask: “Well, Bird, how did I do?”

Presidential families assume a peculiar significance in Washington DC, where trust is at a premium and the professional players always have their own agendas, from the vice-president to the cabinet, to the agencies, to the White House press pool.

The Trump family is by far the most influential White House clan since the Kennedys and perhaps even since Edith Wilson managed the White House after her husband Woodrow’s stroke in 1919, which left him incapacitated.

The Trump family is embedded in this administration and is possessed of enormous influence. Son-in-law Jared Kushner has both domestic and international policy responsibilities, including bringing peace to the Middle East. Daughter Ivanka’s judgment is trusted by the President, as is ­that of Donald Trump Jr. This we know from his Trump Tower campaign meeting last year with the Russian emissaries.

Now the trouble with presidential families is they cannot be disowned by the president. Chiefs of staff, campaign chairs, strategic advisers and press secretaries can all be fired without ­either sentiment or ceremony. Families are forever.

Presidential families generally fall into three broad categories; the powerful; the pestilential; or the privileged.

And the Trump family, with its finances, corporate and political, are close to the core of Special Counsel Robert Mueller’s current inquiries, with Donald Trump Jr at the eye of the storm.

A few days ago in London, former MI6 chief Sir Richard Dearlove made the claim that the Trump empire survived the global financial meltdown courtesy of Russian investors. This is unsubstantiated and may simply reflect the antipathy of both the British and US intelligence communities towards Trump. But if true, this will emerge in Mueller’s investigation; now buttressed by a second grand jury empanelled in Washington DC. Mueller is following a money trail. The presidential unease about this is apparent.

Presidential families generally fall into three broad categories; the powerful; the pestilential; or the privileged.

The powerful would certainly include Eleanor Roosevelt, who carved out an inspiring role as first lady, from the depths of the Great Depression to victory in the Second World War. More than a few first ladies have modelled themselves on ER, who did not hesitate to challenge FDR on policy issues as important as civil rights.

Jacqueline Kennedy brought style and a sense of heritage to the White House. Nancy Reagan ­occupied a powerful place in her husband’s administration as best evidenced by incoming chief of staff, Howard Baker, declaring that he would be talking to the first lady about “whatever she wants”.

But Bobby Kennedy best ­exemplifies the powerful. As Jack’s attorney-general, he undertook every role his brother ­assigned, from presidential emissary during the Cuban missile crisis to the pursuit of the board of US Steel after an outrageous price hike. RFK, however, is the exception where presidential brothers are concerned.

Pestilential nuisances are more frequently on display.

Billy Carter was a continuing embarrassment to his brother, Jimmy, with a beverage “Billy Beer” even named in his honour. Roger Clinton actually received a pardon from half-brother Bill, in an exercise of presidential clemency. Donald Nixon had perhaps the greatest impact on the American presidency. Donald was the beneficiary of a $US205,000 bailout from eccentric billionaire Howard Hughes.

Hughes’ principal lobbyist in Washington was senior Democrat Larry O’Brien, who rose to become chairman of the Democratic National Committee.

It was O’Brien’s office in the Watergate Building that was the target of the White House “plumbers” burglary in June 1972 as they sought evidence of ­Hughes’s “loan”. Ultimately, this brought about the fall of Donald’s brother, Richard M. Nixon.

Donald Trump broke this mould and his family has assumed a powerful place in the taking of spoils.

To date, the Trump family may simply be characterised as privileged, but that may well change. The concentration of power in the Trump offspring is unusual in White House history, although American politics have traditionally been dominated by great political families. The Roosevelt children supported their crippled father throughout FDR’s presidency, in both a physical and emotional sense. There are certain parallels between Anna Roosevelt and Ivanka Trump, given their closeness to their fathers.

However, the Trump family is not born of politics. Its loyalties are personal and tribal, which provides both strength to the incumbent and vulnerabilities for critics bent on destruction. Business dealings loom large.

From the Republic’s earliest days great families have occupied high political office on a recurring basis: the Adams, Harrisons; Roosevelts, and Bushes all providing more than one president. Not to mention the Kennedys, Rockefellers, Gores or Clintons, who have been significant political players in both executive and legislative branches, as well as at state level. To illustrate, in eight of the past 10 presidential races a Clinton or a Bush has appeared on the ticket for Democratic or ­Republican nominees.

This runs counter to traditional American aspirations. To place matters in perspective, the great American presidential historian Arthur M. Schlesinger observed optimistically in 1947: “As a democracy the United States ought presumably to be able to dispense of dynastic families.”

This has not come to pass and Schlesinger’s conclusion remains even more relevant today, as Washington elites supposedly give way to an imperial presidency worthy of Richard Nixon. The US has not ever achieved the status of India, which was often referred to as an hereditary democracy, ­reflected in the centrality of the role of the Gandhi family and the Congress Party. However, on ­occasions it has come close.

Donald Trump broke this mould and his family has assumed a powerful place in the taking of spoils.

However, this position of privilege in Washington DC brings with it not only rigorous scrutiny but also the imposition of very definite accountability.

President Trump’s reliance on his family means Trump Tower in New York City has a third T ­emblazoned upon it. Target.