Indeed, you are projecting God’s commands to His theocracy onto the US of A.
Nebuccanezzar was reduced by God due his pride in claiming credit for what God had done. Where does it say that Nebuccanezzar or some unnamed Samarian King were deposed because they failed to do as God commanded His people?
I know of no place in Scripture where ye find the Lord commanding the governments of countries other than Israel and Judah to care for the poor. He commands His children under the New Covenant to do so (Read James), but not governments. Those are told to punish evil doers and reward those who do good (Romans 13).
Amos 4:1 Hear this word, ye kine of Bashan, that are in the mountain of Samaria, which oppress the poor, which crush the needy, which say to their masters, Bring, and let us drink. 2 The Lord GOD hath sworn by his holiness, that, lo, the days shall come upon you, that he will take you away with hooks, and your posterity with fishhooks.
Daniel 4:27 Wherefore, O king, let my counsel be acceptable unto thee, and break off thy sins by righteousness, and thine iniquities by shewing mercy to the poor; if it may be a lengthening of thy tranquillity. 28 All this came upon the king Nebuchadnezzar.