President Donald Trump's inaugural address ranked highly on consistency. It bore the uncompromising mark of the insurgent sentiments that had pushed Mr Trump from the ideological periphery of the Republican Party - to say nothing of the left-liberal consensus represented by the Democratic Party - to the centre of political power. His swearing-in last Friday followed time-honoured American presidential traditions. However, his address made it clear that he sees himself as a radical wrecker of polite political conventions, and even partisan codes of conduct, in the mission to restore American greatness. In that vein, he declared: "We assembled here today are issuing a new decree to be heard in every city, and in every foreign capital and in every hall of power." He also said: "From this day forward, a new vision will govern our land, from this day forward, it's going to be only 'America first! America first!'"

That promise is an uncontroversial one because every American president owes it to his people to put America first. Leaders of other nations have a similarly nationalist duty to their own people. Friends of America will empathise therefore with President Trump's pain over mothers and children trapped in poverty in the country's inner cities, and over the sight of "rusted-out factories scattered like tombstones". As crime and gangs flourish in that hellish environment, it is natural for any American president to wonder about the usefulness of being the most powerful man on earth if he cannot eradicate the menace within.

However, it is necessary to keep even such challenges in perspective. Mr Trump's vow to stop the "American carnage" was ringing in its rhetorical power, but is it backed up by facts? Similarly, his prescription for an American recovery - based on the promise to "bring back" American jobs, borders, wealth and dreams - has undertones of protectionism that worry many, both in the United States and abroad. His withdrawal of America from the Trans-Pacific Partnership and his vow to confront China suggest an abrasive unilateralism that could erode America's global space. His dramatic desire to wall off the influx of job-seekers from Mexico adds to the problematic astringency of his proposed policies, which take a dim view of international environmental protocols as well. However, his intention to improve ties with Russia and crush the terrorist threat from the Islamic State in Iraq and Syria is a welcome sign of American activism. It should set at rest fears that Mr Trump's America will be isolationist.

Now that he is in power, Mr Trump will need to uphold the economic and strategic symbiosis which binds his country to other nations. American greatness requires a receptive world. By contrast, a myopic America First policy that jeopardises the well-being of other countries could invite unpleasant countervailing responses.