IT all seemed so simple on the campaign trail, at least to Donald Trump and his supporters. For much of 2016, the property tycoon turned presidential candidate prescribed a series of quick fixes for America’s millennial angst.

So he told those worried about immigration that he would put up a giant wall on America’s southern border – and, of course, make the Mexicans pay for it – and he promised those scared of terrorism he would ban Muslims.

The now President Trump came to define the politics of the Twitter age, the politics of simple – or simplistic – solutions to complicated problems. After just a 100 days in office, Mr Trump may be realising the world is not so easy.

His headline-grabbing pledges have flopped: there is no Congressional or, indeed, Mexican, funding for a wall and two successive bans on visitors from mostly Islamic countries have been kyboshed by the courts.

Mr Trump may not always be the most self-aware of politicians. But even he has acknowledged complexity where once he saw only glib soundbites.

“Nobody knew health care could be so complicated,” the president declared as his proposals to overturn so-called Obamacare medical insurance stalled.

Nobody, that is, apart from politicians and commentators inhabiting the old world where policies could have more than the 140-character limit of Mr Trump’s favourite micro-blogging site.

But what now for Mr Trump? His populist campaign promises were – thankfully – always going to be hard to deliver. His angry outbursts against those he believes stand in his way – legislators, judges and news media – suggest frustration.

That may be dangerous, especially if, stymied at home, he seeks new outlets for his simplistic vision on the world stage.

However, Mr Trump, incapable of delivering, may retreat to a social media one-term presidency, tweeting America rather than leading it. This too may bring perils, those of a White House whose only power is to blame others for its own shortcomings.