  It is important to understand how the outcome of an election can be modified
by an agent with control over the structure of the election. Electoral control
has been studied for many election systems, but for all studied systems the
winner problem is in P, and so control is in NP. There are election systems,
such as Kemeny, that have many desirable properties, but whose winner problems
are not in NP. Thus for such systems control is not in NP, and in fact we show
that it is typically complete for $\Sigma_2^p$ (i.e., ${\rm NP}^{\rm NP}$, the
second level of the polynomial hierarchy). This is a very high level of
complexity. Approaches that perform quite well for solving NP problems do not
necessarily work for $\Sigma_2^p$-complete problems. However, answer set
programming is suited to express problems in $\Sigma_2^p$, and we present an
encoding for Kemeny control.
