There will be much to learn in Inspector General Michael Horowitz's upcoming report on the Trump-Russia investigation, but most of it will likely boil down to just two questions. One, how much did the Obama Justice Department spy on the Trump campaign? And two, was it justified? Many Democrats would immediately protest the word "spying." But the public already knows the FBI secured a warrant to wiretap low-level Trump adviser Carter Page a few months after Page left the campaign. The public also knows the FBI used informant Stefan Halper to gather information on other Trump campaign figures. And the...