In 98% of cases "reducible to" is used
It's not reducible to its parts.
And it is not reducible to the elections.
The assemblage is not reducible to its parts.
For what it's worth: Sexism is not simply reducible to the prejudice of individuals.
Modern materialism contends that mental states are reducible to physical brain states.
The 21st Century working class is not reducible to the blue collared industrial worker.
They are not, in particular, reducible to desires or motives, and the reasons we have do not derive from desires.
Such a view would first require some primitive type of physical existence, not reducible to mathematical existence.
The Christological controversies of the Early Church were often reducible to semantics, rather than concrete issues.
Stalinism and reformism are not, however, reducible to physical cow-ardice and paralysis in the face of every danger.
In 1% of cases "reducible from" is used
After all, the Daleks have never been reducible from Doctor Who.