Chris Christie, the governor of the US state of New Jersey, warned last week against the growing appeal of libertarianism in American politics, particularly on matters of national security.
"I just want us to be really cautious," said Mr Christie, a Republican, "because this strain of libertarianism that's going through both parties right now and making big headlines, I think is a very dangerous thought."
The governor was criticising efforts by members of the US Congress to restrict the National Security Agency's surveillance programmes. Congress is restive on this issue because many Americans worry that the NSA is violating their privacy. Among those Mr Christie targeted was Sen Rand Paul; the two men may become rivals for the Republican presidential nomination in 2016.
Unfortunately Mr Christie missed an opportunity to remind his countrymen of an even more dangerous thread running through public and Congressional opinion, namely the tendency towards isolationism - hiding at home in an imagined security cocoon while becoming ever more reluctant to get involved in foreign crises.
President Barack Obama, once hailed for his cosmopolitan background, has been the prime exemplar of a more inward-looking approach to international relations.
This growing isolationism must be qualified. Given global economics and communications, no state can be truly isolated. But a decade of war in Iraq and Afghanistan has made Americans much more wary of overseas commitments. Caution about America's ability to be effective abroad has pervaded many of Mr Obama's foreign policy decisions, above all in the Middle East.
That is what Mr Christie would have been more justified in saying, rather than indirectly defending a surveillance programme that has provoked uneasiness among the public. A recent Pew poll found that 47 per cent of Americans felt that the government's antiterrorism policies had gone too far in restricting civil liberties, while 35 per cent said that they had not gone far enough.
However, the public distress on this issue should not allow Mr Christie to conclude that libertarianism is the most pressing menace to US national security. Ultimately, a more active foreign policy would serve America better than this new isolationism. But Mr Obama has devoted relatively little time and thinking to foreign affairs. Even his vaunted "pivot to Asia" has not materialised as much more than a bid to justify disregarding the Middle East.
America's foreign policy after World War II was built around a combination of realism and idealism. Its post-war strategy was the containment of communism, which blended these two attitudes: There was an idealistic belief that the US would fight communism in an open-ended struggle wherever it manifested itself to defend liberty; and this was based on a realistic view that a hard-nosed attitude and a strong military would let the US embark on this forceful policy.
With the end of the Cold War, America sought a new foreign policy model. While it never defined anything as clear as containment, Washington continued to pursue policies alternatively characterised by values and by a more cynical reading of power relations. Thus, President Bill Clinton intervened in Bosnia in response to the Srebrenica massacre, while George W Bush pursued his "war on terrorism" and the Iraq war by relying on America's military superiority.
Mr Obama has brought no clarity to US foreign policy, and he has shown himself unwilling to take the lead on vital international issues. His administration has downgraded America's hitherto prominent role in the Middle East, and has seemed to be without a strategy in places such as Syria and Egypt. John Kerry, the secretary of state, has just restarted Palestinian-Israeli negotiations, but this has been an exception confirming the rule of US standoffishness.
In Asia, Mr Obama will be pulling troops out of Afghanistan soon, while the US has taken a cautious line on the tensions between China and its Asian neighbours, many of them US allies, over contested maritime areas.
One thing Washington has not done is draw red lines around its allies, to protect them. This may show an understandable desire to avoid a confrontation with China, but it has also meant that the US has been more adept at dealing with situations mainly outside its control than at ensuring that the outcomes are in America's favour.
That seems to be true almost everywhere where the US has been involved, from Europe to Africa to Latin America. The administration has only rarely been proactive, often preferring to follow the lead of other states. Mr Obama has called this "leading from behind", but many have seen desperately little leading by America.
Not surprisingly, there is a cacophony of American views on the country's foreign policy course. Libertarians and some realists have approved of the focus on domestic priorities, with the latter arguing that a stronger America at home means a stronger America abroad. In contrast, other realists have lamented that the US aversion to intervening in the world means it is not protecting its interests.
Liberal interventionists have been dismayed by US indifference to the carnage in Syria and worry about what will happen in Afghanistan once the US pulls out. And neoconservatives mistrust Mr Obama for having defined his foreign policy preferences in opposition to theirs, even if the president has continued Mr Bush's antiterrorism policies, such as the pursuit of drone attacks.
Until the administration resumes a more active role in defining the global agenda and stops affirming that there is little it can do abroad, confusion will reign about America's intentions in the world. Too little of America can be just as destabilising as too much of America.
Michael Young is opinion editor of The Daily Star newspaper in Beirut.
On Twitter @BeirutCalling