Marchamont Nedham published The Case of the Commonwealth of England Stated in early May 1650. Two weeks later, on 24 May, the Council of State voted to pay him £50 “as a gift for service already done” and to confer on him a pension of £100 “whereby he may subsist while endeavouring to serve the Commonwealth; this to be done for one year, by way of probation.” Nedham was not behindhand in seeking to justify this handsome salary and to guarantee its continuance.

On 8 June, he presented to the Council of State a prospectus for a weekly newsbook, “Comprizing the Sūm of all Intelligence wth. the Affaires and Designes now on foot, in the three Nac̄ons, of England, Ireland and Scotland,” to be written “in defence of the Com̄onwealth, and for Informac̄on of the People.” He proposed calling it Mercurius Politicus “because the present Goūnmt is verā πολιτεία as it is opposed to the despotick forme,” and he argued that, if the journal was “to vndeceive the People,” it had to to be “written in a Jocular way” lest it “never bee cryed vp.” It was, therefore, “to sayle in a middle way, between the Scylla and Charybdis of Scurrility and prophanes,” it being Nedham's presumption that “those truths wch. the Multitude regard not in a serious dresse, being represented in pleasing popular Aires, make Musick to ye. Com̄on sence, and charme the Phantsie; wch. ever swayes the Scepter in Vulgar Judgemtp; much more then Reason.”