The French ambassador to the US from 1902 to 1924, Jean-Jules Jusserand, observed that distant powers could not easily threaten the US because “On the north, she has a weak neighbour; on the south, another weak neighbour; on the east fish and on the west, fish”.

The coming of the submarine-based nuclear missile has not changed that. Apart from the fact that no enemy would dare use them for fear of retaliation, and that there is no country in the world that feels that hostile to America (accept North Korea), the fact is America is too big and too far away to be invaded and dominated. There could not be a blitzkrieg by a foreign army across the mid-west or a Vichy America.

The real tragedy of 9/11 is just as a majority of the US electorate had settled into a post-Cold War comfort zone with the new president, George W. Bush, not being overly pushy or confrontational in foreign affairs, America was jolted so badly that a large proportion of its electorate – maybe half – has been paranoid ever since. Enemies are once again seen under the bed.

Enough of the electorate have persuaded themselves that they are insecure – and not just because of growing terrorism – and they have made sure via the Republican majority in Congress that President Barack Obama has had his hands tied on everything from emptying Guantanamo to gun control to pursuing more cuts in nuclear weapons with Russia.

Obama will leave the presidency without having been able to lance this boil. He hasn’t been able to pull his troops out of Afghanistan as promised. Although the US has decided wisely not to involve itself with an invasion of Syria and an attempt to overthrow President Bashar al-Assad of Syria the US is increasingly involved militarily in the upheavals in the Levant.

If the Washington foreign policy elite had felt less intimidated by the fear-mongers in Congress and the American hinterland Obama would have been able to be more of a peace-maker in the style of his Nobel Prize speech and less of a man troubled and walking uneasily along the borders of war and confrontation

In theory it should be not too hard to reduce America’s military foot print because the rational argument for doing so is overwhelming. But in practice the emotional, macho-inclined, irrational minded too often prevail.

What should a rational policy be?

Most important, once the Soviet Union collapsed the US should have sharply reduced its military presence in Europe and turned European security over to the Europeans. Instead under President Bill Clinton – and continued by presidents Bush and Obama – NATO expanded eastwards, now up to the Russian border. Russian interests were ignored. One outcome of this has been the lack of progress on nuclear arms cuts. Another is the confrontation over Ukraine. Another is Moscow’s decision to position itself closer to Beijing.

In the Middle East there should have been no second invasion of Saddam Hussein’s Iraq. Iran and Iraq should have been left to balance each other. Obama repeated the error when the US and the Europeans toppled the dictator of Libya, Muammar al-Quaddafi, when, as now has become clear, he kept the peace inside a country where there were countless factions ready to jump to arms if given latitude.

Which are the vital regions and concerns which America should protect today? Are there places where the US might be replaced at the pinnacle of global power to its detriment?

It is truly hard to think where. If one says China because of its aggressive policies around the islands in the South China Sea then the US will have lost all sense of proportion (as the Chinese probably have themselves).

If one says Ukraine then one has allowed an insignificant tail to wag the European dog. If one says Russia what are the truly divisive issues? Only Ukraine. On Afghanistan, Iran and, to some extent, Syria, they have worked together.

If one says the Middle East and the fixation with its oil, then one has overlooked fracking, solar and wind energy, and the coming revolution in car transportation.

America’s mistakes, some of them leading to long wars, have been costly. The wars in Afghanistan and Iraq have cost $6 trillion. 7,000 US soldiers have been killed and 50,000 wounded, with many of them depressed and some suicidal.

China, in contrast, has stayed out of fighting wars since the Korean war. Unlike the US it has not wasted trillions. Instead it has invested that money in infrastructure, education and technological change. America would be a much stronger power today if it had done the same.

The lesson for today? Come home, stay back and when, on occasion, unprovoked enmity is directed in America’s direction, stay calm and collected.

Free to think clearly, America should be able to find a way out of conflict short of war.