A divided Congress is the single biggest threat to US power abroad, John Kerry, the new secretary of state warned on Wednesday, as he prepared to embark on his first overseas tour as America's top diplomat.
Warning that America must put its finances in order or risk its position of global pre-eminence, Kerry made the economic case for diplomacy as a creator jobs and investment opportunities for US companies.
"The greatest challenge to America's foreign policy today is in the hands not of diplomats but of policymakers in Congress," he said. "It is often said that we cannot be strong at home if we're not strong in the world."
The US is now just 10 days away from the so-called "sequester" that will inflict $85?billion (pounds 55.6?billion) in damaging budget cuts as Democrats and Republicans fail to agree on how the US should rein in its mounting $16?trillion national debt and set a course towards fiscal sustainability.
"My credibility as a diplomat, working to help other countries create order, is strongest when America at last puts its own fiscal house in order, and that has to be now," added Mr Kerry who departs for London on Sunday at the start of a nine-nation tour of Europe and the Middle East.
Making only passing references to America's security challenges with Iran, Syria and the fraying Arab Spring revolutions - and no mention of the Israel-Palestinian conflict - Mr Kerry made an impassioned plea to Americans not to turn inwards and become isolationist during tough economic times.
American diplomacy, Mr Kerry contended, was paying for itself many times over, both in terms of individual contracts won, but also in creating future markets for US exports.
Recalling his own childhood experiences in post-War Berlin, the former Massachusetts senator, said that America must "marshal the courage that defined the Marshall Plan" if it wanted to compete with the new rising powers of the global economy like China and India.
He cautioned against the growing political insularity of much of America, where politicians raise cheap cheers on the stump by presenting the global economy as a threat rather than an opportunity.
"We can be complacent, or we can be competitive as new markets bloom in every corner of the globe - and they will, with or without us," he said. "We can be there to help plant the seeds, or we can cede that power to others.
"Developing economies are the epicentres of growth, and they are open for business, and the United States needs to be at that table. If we want a new list of assistance graduates, countries that used to take our aid but now buy our exports, we can't afford to pull back."
On security issues, Kerry argued that it was short-sighted to give up on soft power investments that gave children the choice of "a walk into a school instead of into a short life of terrorism", and deepened broader loyalty to the US and its democratic value-system.
"Deploying diplomats today is much cheaper than deploying troops tomorrow. We need to remember that," he said.
Justifying foreign aid — a frequent target for fiscal Conservatives who argue such disbursements are unaffordable in austere times — Kerry observed that eleven of America top 15 trading partners had once been the beneficiaries of US foreign assistance.
"In the shadows of World War II, if you told someone that Japan and Germany would today be our fourth and fifth-largest trading partners, someone would have thought you were crazy," he added, citing US exports to Vietnam, where he fought as a young man, had increased sevenfold over the past decade.
The urgent need to mitigate climate change, an emerging theme of Barack Obama's second term, was also framed in terms of economics and trade. The revolution in green technologies, already a $6?trillion dollar market, would lead to unprecedented opportunities said Kerry.