In October, 1680, Lord Russell moved in the House of Commons a resolution that they ought to take into consideration how to oppose Popery and prevent a Popish successor to the throne. A Bill was accordingly brought in for excluding the Duke of York from the crown, which passed the House of Commons, but was thrown out by the Lords, to whom it was carried up by Lord Russell, attended by nearly the whole of the Commons. About the same time Lords Shaftesbury, Russell, and Cavendish presented the Duke of York to the grand jury for Middlesex at Westminster Hall, as indictable, being a Popish recusant. In January, 1680-1, the Commons resolved that "until a Bill be passed for excluding the Duke of York, they could not vote any supply, without danger to His Majesty and extreme hazard to the Protestant religion."

Things had come to this crisis after years of arbitrary power, and the humiliation of England in its king being a pensioner of Louis XIV. As far back as 1669 a secret treaty was made with France, Charles engaging to declare war against Holland, France to pay the king £800,000 annually and make a division of the conquests, of which France would have the largest share. In 1670 Colbert mentions Charles's ratification of this treaty, having the king's seal and signature, and a letter from his own hand. This treaty was kept secret from his ministers, and a pretended treaty (un traitÉ simulÉ) was to be promulgated, to which the Protestant members of the Cabinet were to be parties. Colbert further states that he was told in confidence by the Duke of York that the king was ready to declare himself a Catholic, and that he was determined to rule independently of any parliament. The object of Charles was mainly to obtain money from the French king, but the Duke of York had deeper and more dangerous plots to carry out. The marriage of the Princess Mary to the Prince of Orange in 1677 somewhat disturbed the understanding, but a renewal of the treaty in 1678 brought England again to lie at the mercy of the French king. The impeachment of Lord Danby, Lord Treasurer, for the part taken by him in these disgraceful transactions, showed that there were still many Englishmen prepared to act for the honour and freedom of their country. To Lord Russell most men looked as the leader of the patriotic party, and it was determined to get him out of the way as the chief opponent of the arbitrary power of the king and the Popish designs of his brother, who showed the most unrelenting hatred of Russell. It was resolved that he should be brought to trial for treason, as compassing the overthrow of the government of the king. He was arrested on January 26, 1683; after examination was committed to the Tower the same day, and afterwards removed to Newgate.

Lord Russell was found sitting in his study, neither seeking to conceal himself nor preparing for flight. As soon as he was in custody, he gave up all hopes of life, knowing how obnoxious he was to the Duke of York, and only thought of dying with honour and dignity. The Earl of Essex was at his country house when he heard of the arrest of his friend. He could have made his escape, and when pressed by his people to fly, he answered that "his own life was not worth saving if, by drawing suspicion on Lord Russell, it might bring his life into danger." He was taken to the Tower, where, it was announced, he killed himself on the morning of Lord Russell's trial. It is more probable, as was generally believed, that he was murdered, and the report of suicide was spread in order to strengthen the charges against Russell. Monmouth had disappeared, but, actuated by the same generous motive with Essex, he sent a message to Russell, on hearing of his arrest, that "he would surrender himself and share his fate, if his doing so could he of use to him." Russell answered in these words: "It will be of no advantage to me to have my friends die with me."