We now want to see how far a variational approach--i.e., an approach based on analyzing the first (and second) variation of the cost functional--can take us in studying the optimal control problem formulated in Section 3.3. We will find that with minimal extra work, this familiar approach allows us to arrive at the correct statement of the maximum principle for a specific problem setting. We will also discover that in general, this approach has serious shortcomings which will force us to turn our attention to a different, richer class of perturbations.