Connections between the declaration of independence and the second principle, social contract.

 the Declaration of Independence and the second principle indicate that the most basic human law of nature is the preservation of man kind.Individuals have both a duty and a right to preserve their own lives. This makes people have the full rights about their choice of jobs, religions, sexual partner, etc.
If the government persecutes its own people with"a long train of abuses"  by limiting their freedom, it will come a day when the people gonna revolt and overthrow the government.