It is in fact the DUTY of govt TO protect Life (, Liberty and the Pursuit...).
Not only did CONGRESS abrogate its responsibility, the States did so as well; and ultimately, We the People allowed all 3.
“Cherish, therefore, the spirit of our people, and keep alive their attention. If once they become inattentive to the public affairs, you and I, and Congress and Assemblies, judges and governors, shall all become wolves. It seems to be the law of our general nature.” - Thomas Jefferson (Letter to Edward Carrington January 16, 1787)