Oliver St John was born in Bedfordshire, circa 1598. After attending Queen's College, Cambridge, and Lincoln's Inn, he was called to the bar in 1626. He made an advantageous marriage to heiress Joanna Altham around 1629 despite the doubts of her family regarding his suitability. The marriage also brought a family connection with Oliver Cromwell and John Hampden. After Joanna's death, St John's second marriage (1639) was to Elizabeth Cromwell, a cousin of Oliver's. During the 1630s, St John was retained as a lawyer by the Earl of Bedford through whom he came into contact with the affairs of the Providence Island Company, whose members included Lord Saye, John Hampden, John Pym and other future leaders of the opposition to King Charles.
St John rose to national prominence in 1637 when he served as legal counsel to Lord Saye and John Hampden in their challenge to the legality of King Charles I's imposition of Ship Money. Although the judges found against Hampden, the case was widely regarded as a moral victory against the King's arbitrary use of his powers.
Elected to the Short Parliament as MP for Totnes in 1640, St John caused uproar by proposing that Parliament should intervene to overturn the Ship Money judgment. He also questioned the legality of the dissolution of the 1629 Parliament and argued that Laud's reforms of the Church were not binding unless ratified by Parliament. When the King dissolved Parliament, St John worked closely with Pym in petitioning for its recall. He was duly elected to the Long Parliament and resumed his challenge to the Ship Money judgment by introducing the impeachment of the magistrates who had presided over the case, prompting Lord Keeper Finch to flee abroad rather than face the charges brought against him.
St John was appointed Solicitor-General in January 1641 at the instigation of his patron the Earl of Bedford, who advised the King to appoint ministers trusted by Parliament. This did not prevent St John from taking a leading role in the impeachment of the Earl of Strafford and supporting the Act of Attainder by which Strafford was condemned to death. However, St John also proposed measures for financial reform that were advantageous to the King. As Solicitor-General, he played a double game by appearing to be working on the King's behalf while still promoting a radical agenda. In May 1641, he drafted the bill for the abolition of Episcopacy, arguing that the bishops had usurped powers that properly belonged to civil magistrates, yet he covered his tracks by persuading Sir Edward Dering to introduce the bill into Parliament. In a similar subterfuge, he drafted the provocative Militia Bill in December 1641, but it was Sir Arthur Haselrig who introduced it in the House of Commons.
When the First Civil War broke out in 1642, St John emerged as one of the leaders of the "War Party" that was intent on inflicting a decisive defeat on the King rather than attempting to reach a negotiated settlement. He was prominent in negotiating the Solemn League and Covenant for an alliance with the Scots in 1643. After the death of John Pym in December 1643, St John and Sir Henry Vane came to be regarded as leaders of the House of Commons. He worked closely with Oliver Cromwell in promoting the Self-Denying Ordinance as a means of improving Parliament's military capability, and secured Cromwell's exemption from the Ordinance after the creation of the New Model Army. In order to maintain the Scottish alliance without committing Parliament to a Presbyterian religious settlement, St John was instrumental in reviving the impeachment proceedings against Archbishop Laud, who was beheaded in January 1645.
After the defeat of the King in the First Civil War, St John continued to cooperate with Cromwell and the Grandees, who were now seeking to limit the power of the Monarchy. St John helped in the drafting of the Four Bills (December 1647) in the hope of reaching a moderate settlement, but the King's alliance with the Scottish Engagers alienated the Army leaders and provoked the Second Civil War in 1648. The Army denounced King Charles as "the Man of Blood" and demanded that he be brought to account. St John began to fear that a military tyranny might replace the King's tyranny. He became associated with a group of moderates led by Lord Saye who took steps to distance themselves from the militants.
In October 1648, St John was appointed Lord Chief Justice of the Court of Common Pleas. He devoted himself to his judicial duties. He was nominated to be one of the King's judges but refused to take up the appointment, so had no direct involvement in the events that culminated in the execution of King Charles I in January 1649. However, St John maintained contact with Cromwell and was nominated to the first Council of State in February 1649.
Early in 1651, St John and Walter Strickland led a diplomatic mission on behalf of the Commonwealth to the United Provinces of the Netherlands. The main purpose of the mission was to seek an alliance in the interests of Protestant unity against the Papists. It was also hoped that the Dutch could be dissuaded from giving any support to the Stuarts and their followers. The mission was fraught with danger — the Commonwealth envoy Dr Dorislaus had been murdered by Royalist exiles in 1649. On their arrival at The Hague in March 1651, St John and Strickland were harangued and threatened by Royalists. The powerful House of Orange opposed a union with the regicide Commonwealth, and calls for the expulsion of English Royalists were firmly rejected. The failure of the diplomatic mission is said to have motivated St John to formulate the first Navigation Act, passed by Parliament in October 1651, with the intention of damaging Dutch trade.
Following the Commonwealth's military conquest of Scotland, St John was one of the Commissioners appointed to set up the new civil administration. He arrived in January 1652 to supervise the re-organisation of the courts of law. He also participated in the negotiations for the incorporation of Scotland into the Commonwealth with England and Ireland. He remained loyal to Cromwell throughout the Protectorate and supported the offer of the Crown to Cromwell in 1657.
After the Restoration in 1660, St John published an account of his past conduct, The Case of Oliver St John. He was known to have been deep in the counsels of the Commonwealth and was vilified in the writings of Clarendon and Holles. However, no incriminating evidence could be found and his only punishment was exclusion from public office. He retired to his house in Northamptonshire until 1662, then went into exile, first at Basel then to Augsburg in Germany where he died in December 1673.
References:
C.H.Firth, Oliver St John, DNB, 1897
Craig Muldrew, Oliver St John: the Dark Lanthorn of the Commonwealth, Queen's College Record, 2002
William Palmer, Oliver St John, Oxford DNB, 2004