Barack Obama issues his last executive order

Despite the promise of more harmonious race relations under President Obama, however, Chicago remains a city wracked by gun violence. Last year, it accounted for more homicides (nearly 800) than New York and Los Angeles combined, much of it involving African-Americans and Latinos. This dreadful reality serves as something of a metaphor for the Obama presidency, and of presidencies of general: occupants of 1600 Pennsylvania Avenue may carry the nuclear football, but their ability to initiate change on Main Street, USA, is heavily constrained.

Mr Obama's election in 2008 was invested with unusually high hopes, largely as a result of his inspiring rhetoric, his promise of a mature approach to government (after the recklessness of George W. Bush years), and of course his skin colour. Unfortunately, the Global Financial Crisis intervened before key campaign promises could be implemented.

Counteracting the near-catastrophic effects of the GFC occupied most of Mr Obama's first term. Critics lamented his slow progress and his unwillingness to enact regulatory reforms designed to prevent a reoccurrence of the property bubble that had precipitated the crisis. However, Mr Obama's success in overcoming the deepest recession in 70 years remains one of two noteworthy features of his first term – the other being the Affordable Care Act of 2010 which extended health insurance to nearly 10 million Americans who'd previously been unable to afford cover.

As with previous administrations, the Obama White House's focus on foreign policy grew with time. But here too, Mr Obama discovered his aspirations (which included extricating US forces from Afghanistan and Iraq, closing the Guantanamo Bay detention camp, progressing the two-state solution in Israel, and initiating action on climate change) were constrained by domestic political considerations. The Iran nuclear deal was a notable exception to that general rule.

Mr Obama has been criticised, perhaps fairly, for his unwillingness to argue and to haggle with his opponents in the way that, say, Ronald Reagan or Lyndon Johnson went about winning support for their legislative agendas. If not a natural-born politician, however, Mr Obama was a firm believer in applying reason and logic to political conundrums. One outcome of this cerebral approach was Mr Obama's refusal to entangle the US in foreign adventures with no reasonable hope of quick resolution. That prudent watchfulness, and the sense of decency and dignity that he brought to the job, will stand as one of the brighter legacies of the Obama presidency.