The state legitimately defends its citizens against foreign invaders.
The biggest killers in time of war, e.g., invading armies, is not the military action itself, but the disease, malnutrition and exposure to the elements that these invading armies inflict upon the citizens.
So, arguably, when defending its citizens against an invading army the state is not primarily tasked with defending its citizens against a bloodless coup, but against agents that inflict disease, malnutrition and exposure on its citizens.
But, if THAT is true, then the state's duty to defend its citizens should also involve defending its citizens against those deleterious effects regardless of whether an army is invading.
Which means the state has a duty to make sure its citizens are at least somewhat protected against those three things under all circumstances. This means the state has the duty to conduct, say, nation-wide vaccination campaigns to wipe out smallpox and polio, mandate campaigns against vitamin-deficiency and malnutrition (which contribute to disease spread in addition to being threats in their own right).
You see where this is going.
IF we admit, as the Constitution does, that the state has a duty to protect its citizens, THEN arguments about the nation's duty to commit acts of social justice are really just variations on an argument over where the "defense" line is drawn.