On the first vacancy which afterwards occurred in the office of solicitor general, he was appointed to fill it; and Sir Thomas Coventry, the attorney general, expressed high satisfaction at having him for a colleague. Very important proceedings soon after followed, upon the impeachment of Lord Bacon and the punishment of the monopolists; but, as these were all in Parliament, he made no conspicuous figure during the remainder of the reign of James I.

Soon after the commencement of the reign of Charles I., he was promoted to the office of attorney general; and then, upon various important occasions, he delivered arguments in support of the unlimited power of the crown to imprison and to impose taxes, which cannot now be read without admiration of the learning and ingenuity which they display.

The first of these was when Sir Thomas Darnel and his patriotic associates were brought by habeas corpus before the Court of King’s Bench, having been committed in reality for refusing to contribute to the forced loan, but upon a warrant by the king and council which did not specify any offence. I have already mentioned the speeches of their counsel.[54] “To these pleadings for liberty,” says Hallam, “Heath, the attorney general, replied in a speech of considerable ability, full of those high principles of prerogative which, trampling as it were on all statute and precedent, seemed to tell the judges that they were placed there to obey rather than to determine.”

“This commitment,” he said, “is not in a legal and ordinary way, but by the special command of our lord the king, which implies not only the fact done, but so extraordinarily done, that it is notoriously his majesty’s immediate act, and he wills that it should be so. Shall we make inquiries whether his commands are lawful? Who shall call in question the justice of the king’s actions? Is he to be called upon to give an account of them?”

After arguing very confidently on the legal maxim that “the king can do no wrong,”[55] the constitutional interpretation of which had not yet been settled, he goes on to show how de facto the power of imprisonment had recently been exercised by the detention in custody, for years, of Popish and other state prisoners, without any question or doubt being raised. “Some,” he observed, “there are in the Tower who were put in it when very young: should they bring a habeas corpus, would the court deliver them?” He then dwelt at great length upon the resolution of the judges in the 34th of Elizabeth in favor of a general commitment by the king, and went over all the precedents and statutes cited on the other side, contending that they were either inapplicable or contrary to law. He carried the court with him, and the prisoners were remanded without any considerable public scandal being then created.

During the stormy session in which the “Petition of Right” was passed, Heath, not being a member of the House of Commons, had very little trouble; but once, while it was pending, he was heard against it as counsel for the king before a joint committee of Lords and Commons. Upon this occasion he occupied two whole days in pouring forth his learning to prove that the proposed measure was an infringement of the ancient, essential, and inalienable prerogatives of the crown. He was patiently listened to, but he made no impression on Lords or Commons; and the king, after receiving an assurance from the judges that they would effectually do away with the statute when it came before them for interpretation, was obliged to go through the form of giving the royal assent to it.

As soon as the Parliament was dissolved, Heath was called into full activity; and he now carried every thing his own way, for the extent of the royal prerogative was to be declared by the Court of King’s Bench and the Star Chamber. Sir John Eliot, Stroud, Selden, and the other leaders of the country party who had been the most active in carrying the “Petition of Right,” were immediately thrown into prison, and the attorney general having assembled the judges, they were as good as their word, by declaring that they had cognizance of all that happened in Parliament, and that they had a right to punish whatsoever was done there by Parliament men in an unparliamentary manner.

The imprisoned patriots having sued out writs of habeas corpus, it appeared that they were detained under warrants signed by the king, “for notable contempts committed against ourself and our government, and for stirring up sedition against us.” Their counsel argued that a commitment by the king is invalid, as he must act by responsible officers; and that warrants in this general form were in direct violation of the “Petition of Right,” so recently become law. But Heath still boldly argued for the unimpaired power of arbitrary imprisonment, pretending that the “Petition of Right” was not a binding statute. “A petition in Parliament,” said he, “is no law, yet it is for the honor and dignity of the king to observe it faithfully; but it is the duty of the people not to stretch beyond the words and intention of the king, and no other construction can be made of the ‘Petition’ than that it is a confirmation of the ancient rights and liberties of the subject. So that now the case remains in the same quality and degree as it was before the ‘Petition.’” He proceeded to turn into ridicule the whole proceedings of the late Parliament, and he again went over the bead-roll of his precedents to prove that one committed by command of the king or Privy Council is not bailable. The prisoners were remanded to custody.

In answer to the information, it was pleaded that a court of common law had no jurisdiction to take cognizance of speeches made in the House of Commons; that the judges had often declared themselves incompetent to give an opinion upon such subjects; that the words imputed to Sir John Eliot were an accusation against the ministers of the crown, which the representatives of the people had a right to prefer; that no one would venture to complain of grievances in Parliament if he should be subjected to punishment at the discretion of an inferior tribunal; that the alleged precedents were mere acts of power which no attempt had hitherto been made to sanction; and that, although part of the supposed offences had occurred immediately before the dissolution, so that they could not have been punished by the last Parliament, they might be punished in a future Parliament. But

Heath, A. G., replied that the king was not bound to wait for another Parliament; and, moreover, that the House of Commons was not a court of justice, nor had any power to proceed criminally, except by imprisoning its own members. He admitted that the judges had sometimes declined to give their judgment upon matters of privilege; but contended that such cases had happened during the session of Parliament, and that it did not follow that an offence committed in the house might not be questioned after a dissolution.