Foreign policy titan Henry Kissinger has made a dubious endorsement of Jared Kushner as a key advisor to Donald Trump.

In less than 150 words, Dr Kissinger – who was notorious for his diplomatic manoeuvring and cunning – dedicated "lukewarm" praise to mark Mr Kushner’s addition to TIME’s 100 most influential people of 2017.

Critics of the Trump administration have criticised the President’s decision to make his son-in-law a senior advisor with responsibility for a wide range of duties. Despite having no previous government experience, Mr Kushner must now tackle America’s insidious opioid epidemic and also work to secure peace between the Israelis and Palestinians.

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“Transitioning the presidency between parties is one of the most complex undertakings in American politics,” Dr Kissinger wrote. “The change triggers an upheaval in the intangible mechanisms by which Washington runs: an incoming President is likely to be less familiar with formal structures, and the greater that gap, the heavier the responsibility of those advisers who are asked to fill it.

He added: “This space has been traversed for nearly four months by Jared Kushner, whom I first met about 18 months ago, when he introduced himself after a foreign policy lecture I had given. We have sporadically ¬exchanged views since.

“As part of the Trump family, Jared is familiar with the intangibles of the President. As a graduate of Harvard and NYU, he has a broad education; as a businessman, a knowledge of administration. All this should help him make a success of his daunting role flying close to the sun.”

Observers highlighted Dr Kissinger’s apparent reference to the Greek mythological character Icarus – who dies after his waxen wings melt as he flies too near the sun.

The letter also failed to point out anything which suggested Mr Kushner is particularly suited for the job.

“This is basically the letter of recommendation you never want an advisor to send,” said Ben Denison, a PhD student at the University of Notre Dame. Ian Bremmer, a prominent political scientist and founder of Eurasia Group, called it “faint praise”.

TIME 2016 Person of the Year Shortlist Show all 11 1 /11 TIME 2016 Person of the Year Shortlist TIME 2016 Person of the Year Shortlist Simone Biles Getty TIME 2016 Person of the Year Shortlist Feng Zhang Getty TIME 2016 Person of the Year Shortlist Dr Mona Hanna-Attisha Getty TIME 2016 Person of the Year Shortlist Hillary Clinton Getty TIME 2016 Person of the Year Shortlist Recep Tayyip Erdogan Vasily Fedosenko/Reuters TIME 2016 Person of the Year Shortlist Nigel Farage Pcture: Getty TIME 2016 Person of the Year Shortlist Beyoncé Getty Images TIME 2016 Person of the Year Shortlist Narenda Modi Getty TIME 2016 Person of the Year Shortlist Vladimir Putin Getty TIME 2016 Person of the Year Shortlist Donald Trump TIME 2016 Person of the Year Shortlist Mark Zuckerberg Getty Images

Journalist Katherine Krueger described the letter as “hilariously lukewarm”.