It is entirely up to us whether we
lift the world to new heights or let it fall
into a valley of disrepair.
As the world's only superpower, with an unmatched network
of alliances, America is often referred to
as the world's policeman.
But with the US police force now led by Sheriff Donald Trump,
its behaviour is increasingly unpredictable.
And, partly as a result, many of the world's rougher
neighbourhoods - from the Persian Gulf to the South China
Sea - are entering an uncertain and dangerous period.
Of course, all of these regional flashpoints
have deep local roots.
But it is also true that uncertainty
about American foreign policy is adding
to the sense of instability.
Take Iran.
For a while, the Trump administration
seemed to be pursuing a clear, if risky, policy.
It withdrew the US from the Iran nuclear accords
and seemed willing to risk a military confrontation.
But in June, Mr Trump abruptly cancelled an airstrike on Iran
that was intended to punish Iran for shooting down an American
drone.
And that's left a legacy of uncertainty,
and may have encouraged the Iranians to take further risks,
seizing three oil tankers in the Strait of Hormuz
in recent weeks.
Then there is the dangerous flare-up in Kashmir.
This also took place against a backdrop of confusing signals
from the White House.
In July, Mr Trump suggested that India
had asked him to mediate with Pakistan
over Kashmir, a statement that was immediately
denied by India.
Shortly afterwards, Delhi moved to abolish
the autonomy of the province of Jammu and Kashmir.
And that move has led to a surge in tensions
with Pakistan, with America watching from the sidelines.
And then there is Hong Kong.
The government of China is hinting
heavily at military intervention there
to suppress months of demonstrations.
A traditional US administration would express support
for the aspirations of the people of Hong Kong
and urge restraint on Beijing.
But Mr Trump has instead called the protests "riots".
On other contentious issues in East Asia
where tensions are rising, US policy is also confusing.
If China ever followed through on its frequent threats
to invade Taiwan, would the US fight to defend the Taiwanese?
The Trump administration has sent very mixed signals,
warming up dramatically the Taiwanese
at the beginning of the administration,
and then backing off.
A similar confusion reigns over the South China Sea.
The US has stepped up naval patrols there
to push back against China.
But President Trump himself regularly
questions the value of America's key alliances in East Asia,
with Japan and South Korea.
And then there is North Korea.
Mr Trump clearly greatly values his friendship
with the North Korean dictator Kim Jong Un.
But North Korea's recently restarted missile tests
and has done very little to deliver on its promise
to get rid of nuclear weapons.
So how long can the Kim-Trump rapprochement last?
Finally, there's Europe.
When it comes to the long-running conflict
in Ukraine, the Trump administration
has toughened US policy by supplying
the Ukrainian government with weapons.
On the other hand, Mr Trump himself
seems to want a much closer relationship with Russia
and with President Putin.
And he sometimes questioned the value of the Nato alliance,
sending shivers down the spine of America's European allies.
So how would Mr Trump react if there was an intensification
of the conflict in Ukraine?
The fact is, nobody can be sure.
And that's also true for all those other regional conflicts.
An unpredictable America poses new dilemmas for other world
powers whose policies increasingly
are based on guesswork about how the Trump White
House may behave.
As a result, uncertainty that begins in the Oval Office
spreads around the world, creating
waves of instability and trouble spots thousands of miles
from Washington.