By Jonathan Beale
BBC US State Department correspondent
Condoleezza Rice will have to tread carefully in this region in which both Russia and China have strategic interests, as she begins a tour taking her to Kyrgyzstan, Afghanistan, Kazakhstan and Tajikistan.
Uzbekistan has asked the US remove its air base there
She wants to reinforce President George W Bush's message of spreading "freedom" without causing too much offence.
Countries in Central Asia continue to be important allies in America's war on terror. Kyrgyzstan, along with Uzbekistan, has provided the US with former Soviet bases from which it has mounted missions into neighbouring Afghanistan.
Tajikistan, Kazakhstan and Kyrgyzstan all have large Muslim populations. The US needs them to counter Islamic extremism.
And this region is a major route in the narcotics trade - all important reasons for Ms Rice to make friends not enemies.
Field of influence
The US plays down talk of a power struggle in this region, but China and Russia are flexing their muscle and exerting influence.
Moscow historically has looked at much of the region as "their territory" - part of the former Soviet Union.
There are good reasons to continue the ties: a large Russian population, and Kazakhstan's oil supplies.
Russia, China, Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan are all members of the Shanghai Co-operation Organisation.
The group's primary aim seems to be to curb Washington's influence.
In July its members signed a declaration calling for a timetable to be set for the closure of US military bases in Uzbekistan and Kyrgyzstan.
Ms Rice will be celebrating the successful Afghan elections
Another reason for the US secretary of state not pressing too hard on the pace of democratic and economic change.
America's most senior diplomat for the region has already signalled the softer tone.
Assistant Secretary of State Dan Fried said "the art of diplomacy and foreign policy making is taking principles, sticking to them, but applying them in the real world in ways that make sense."
Ms Rice herself talks of giving countries time and space to find their own democratic path. In other words too much pressure may prove counterproductive.
Not long ago Uzbekistan was seen as one of America's most important allies in the region. President Islam Karimov provided tough leadership to combat the threat posed by Islamic extremism.
He also allowed the US to use an airbase in the country for missions against the Taleban.
But the relationship has since soured and deteriorated.
The violent suppression of a protest against his regime in Andijan last May brought widespread condemnation.
The US was slow off the mark to join in the criticism, but has since added to international demands for an independent investigation into the killings which left hundreds dead.
Mr Karimov has refused - and to add insult has told the US they must leave the base at Khanabad.
This illustrates the dilemma for Ms Rice. Uzbekistan is a country that has now turned to Russia instead.
This will be Ms Rice's second visit to Afghanistan as secretary of state.
Last time she pressured President Hamid Karzai to set a date for parliamentary election.
This time she wants to celebrate the fact that they have taken place.
But Afghanistan still has security problems. Freedom may be on the march... but its still very fragile.