"presidential candidate should be surveilled for something as dubious as the Steele dossier?"
A presidential candidate running for the presidency of the biggest Military in the world, with nuclear capabilities? Hell yes. If they were closey observed you'd never have had the Russia investigation in the first place. Thats a great idea, to make sure future prez of USA don't get in via corrupt ways they should be observed 24/7. It should apply to both Dems and Reds.