First, we should acknowledge that neither Britons nor Americans agreed amongst themselves about politics, including the nature of the proper relationship between the colonists and Great Britain. Some members of Parliament, and other public and political British figures, openly supported American protests against the British, at least until the Declaration of Independence. Likewise, many Americans believed in remaining loyal to the Crown, and among these Loyalists there were both reform-minded liberals and conservative hardliners.

To the extent we can generalize, mainstream public opinion in Great Britain and the colonies would have agreed on the principles of limited, representative government. They generally approved of the concept of a constitutional monarch, and they agreed that individuals had certain rights, including protection from arbitrary arrest and imprisonment, protection from arbitrary taxation, the right to petition legislatures, and so on. The biggest differences between the colonists and the rulers of Great Britain had to do with how these rights and privileges—most famously the protection against taxation without representation—applied to the colonies.

The colonists claimed that they, as British subjects, could only be taxed by their own assemblies, where they were represented. Parliament, on the other hand, asserted the right to legislate for the colonies, including the right to tax. The imperial crisis revealed other differences as well, relating to the sanctity of the right to a jury trial and the right to regulate such international commerce as the slave trade. So, in short, the colonists, or at least those who became revolutionaries, believed that their rights as British subjects were identical to those in Britain itself (however, they also believed that Parliament could not fully represent them). The ideological differences between these two groups were not all that fundamental on paper, but in practice, they became irreconcilable.

The political differences between the American colonists and the British were more differences of degree and differences of interests than they were differences in political ideologies.  It is not as if the British believed in an absolute monarchy while the Americans believed in democracy.  They both believed in the same basic ideas of limited government and personal rights, but they differed as to where the limits on government should be and they differed on who got to decide such issues.

Both the British and the colonists believed, for example, that people should have some say in their taxation.  British political history included many instances in which the monarchy was forced to allow Parliament more of a say in deciding when and how much people were to be taxed.  The colonists, however, felt that they should directly decide how much they should be taxed.  They believed that taxes that did not have to do with trade (like the Stamp Tax) could not be levied on them by Parliament because they were not directly represented in Parliament.  Thus, they and the British both agreed that people should be represented in the body that decided on taxation, but they did not agree on what constituted representation.

As another example, both the British and the Americans agreed that people should have some degree of rights.  They both believed that government should not simply be able to create a police state.  However, the colonists believed this to a greater degree, particularly because believing this was in their economic interests.  Many Americans were violating British laws on things like smuggling and naturally did not want the government to have as much power to do things like searching and seizing their property.

The colonists wanted more freedom from Britain.  They wanted to be able to have more self-government.  They wanted the government to have fewer police powers.  These were not major philosophical differences.  They were more of differences of degree and differences in economic and political interests.