In Thoughts on Government, Adams asserted that a good government is a government of laws, and considered how the "divine science of politics" could achieve such a government. Adams's proposed solution: three separate, independent, and balanced branches:
- An executive (governor) who would have "a negative upon the legislative"; that is, veto power;
- A bicameral (two house) legislature, as a unicameral (one house) legislature is "liable to all the vices, follies, and frailties of an individual" ; and
- An independent judicial branch.
Adams's most original contribution was his proposal for an independent judiciary. Supreme executives had headed other governments, and the British Parliament had long consisted of two chambers.* Judges, however, were subject to the will of kings and parliaments.
In Adams's compelling words:
The dignity and stability of government in all its branches, the morals of the people, and every blessing of society depend so much upon an upright and skillful administration of justice, that the judicial power ought to be distinct from both the legislative and executive, and independent upon both, that so it may be a check upon both, as both should be checks upon that. The judges, therefore, should be always men of learning and experience in the laws, of exemplary morals, great patience, calmness, coolness, and attention. Their minds should not be distracted with jarring interests; they should not be dependent upon any man, or body of men. To these ends, they should hold estates for life in their offices; or, in other words, their commissions should be during good behavior, and their salaries ascertained and established by law.
Thoughts on Government provided a blueprint for numerous state constitutions, including those of Massachusetts, New York, North Carolina, and Virginia.
* The Province Charter, which governed the colony of Massachusetts from 1691 to 1774, provided for a Royal Governor and a bicameral assembly, known as the Great and General Court. The House of Representatives was elected; the Provincial Council was elected by members of the House, subject to the Royal Governor's veto.