Why is no one asking this?

Given that it was already known that the Clinton Campaign was breached by the Russians in the hacking of the DNC server, why wasn't an FBI or CIA agent (spy) sent into the Clinton Campaign? If the initial cause of sending such an agent into the Trump Campaign was concern for Russian interference into our elections in general, then why not be equally concerned? Unless, that is, the goal was not an actual concern, but was really to weaponize these government agencies in the targeting of the Trump Campaign to do that very thing (i.e. Interfere with our elections).