Why were the americas not as susceptible to overtaking by other countries during about the 1940s? who dominated the world militarily at that time?

the main reason that the constitution did not proclaim all men to be free and equal is because of the issue of slavery.

the answer to your question is a because laws act as guidelines as to what is accepted in society. without it there would be conflicts between social groups and communities. it serves as a norm of conduct for citizens.