By Jill McGivering
BBC correspondent in Washington
The United States has seemed determined to keep the crisis in Sudan's western Darfur region high on the international agenda in recent weeks.
The US has praised Sudan over its co-operation on terrorism
Pressure has been maintained on the Sudanese government by the US administration to take concrete and immediate action to defuse the situation.
But what factors are driving its policy in the region?
The US has learnt painful lessons in Africa.
In Somalia, it was criticised for failing to pay attention to a rapidly worsening situation. Intervention when it came was painful and protracted.
And in dealing with Darfur, everyone is haunted by memories of genocide in Rwanda.
The Clinton administration's failure to respond quickly then brought considerable embarrassment.
Moral high ground
Now US Secretary of State Colin Powell seems determined to avoid those mistakes.
His recent visit to Sudan was a display of US commitment.
His stern rhetoric also signalled another plus point: in the midst of controversy over Iraq, Darfur is an issue on which the US can safely assume the moral high ground, with little international opposition.
Washington has already invested considerable time and energy pressing for a settlement of the North-South conflict.
The focus on Sudan is a key part of its war on terrorism, with the US keen to stop Sudan emerging as a safe haven for Islamic militant groups.
It now publicly congratulates the Sudanese government for its co-operation on terrorism - a partnership it is keen to maintain.
A tougher question is how far the US is prepared to go if Sudan stays troublesome.
So far, its warnings have focused on the threat of a new UN resolution, leading perhaps to multinational sanctions.
The US does not have a lot at stake economically itself.
After all, it still has wide-ranging sanctions against Sudan in place.
More painful would be the prospect of international intervention on the ground.
With so much domestic concern about US troops in Iraq and Afghanistan, any fresh commitment, especially in a region as large and troublesome as Darfur, would be very hard to sell.