North American colonists were taken over by a sense of want for freedom and liberalism which ended up reflecting in their constitution.
Step-by-step explanation:
Britain was one of the most stable monarchies of its time riddled with class differences and relative lack of freedom. US colonies had been established by people who moved there to live on their own terms and to make a better society from scratch.
Thus, when they finally got the chance to make their society on their own terms, they did it to value the moral and ethical codes they had moved to US for.
These were the things like freedom, pursuit of happiness and liberty that they put a focus on.