Campbell at once began to report cases decided at "nisi prius" ("i.e." on jury trial). Of these reports he published four volumes; they extend from Michaelmas 1807 to Hilary 1816. Campbell also devoted himself to criminal business, but failed to attract much attention behind the bar. It was not till 1827 that Campbell took silk and began to develop political aspirations. He had unsuccessfully contested the borough of Stafford in 1826, but was returned for it in 1830 and again in 1831. He stood as a moderate Whig, in favour of the connection of church and state and opposed to triennial parliaments and the secret ballot. His main object, like Lord Brougham, was the amelioration of the law by the abolition of cumbrous technicalities rather than the assertion of new principles.