Has mass immigration strengthened or weakened American society?

11/22/1963 the date of inception of a principle change in America. Lyndon Johnson was sworn in as President on that fateful day. The shock of that event and the institution of the commission to investigate it, was a farce, a coverup on a scale that defies description. If truth be exposed and an accurate investigation were conducted we might discover that elements of the US Government were heavily involved. Then, good old Lyndon used the camouflage of confusion of that event to institute a change in the American mindset. In 1965 the US Congress passed the Hart/Cellar act, that changed drastically who was allowed to immigrate to this nation. Prior to the passing of that act the majority of immigrants where from Northern Europe, parchment skinned from nations that produced people that came here to be Americans, yo assimilate. After Hart/Cellar, which was championed by Ted Kennedy, a radical, but slow, change began. No longer were northern Europeans favored, the majority of immigrants were from Africa or Latin America. The population of our large cities plummeted caucasians being replaced by people that came from different cultures, many that refused to assimilate, that clung to the cultures of their home country, refused to learn our language, and formed enclaves that both magnified their detachment from absorption into the American way of life. We are experiencing the results now. Our major cities that were heavily caucasian are now heavily populated by dark skinned immigrants and IF truth be shown, have crumpled in both production, adding to our GDP, and have become havens for leeches, those that live off the efforts of others. Examine the political nature of most big cities most, if not all, are mired in efforts to become, not examples of American ingenuity, but examples of 3rd world principles dedicated to, not advancement but to destruction of society, replacing effort with a pleading of sustainment.
My composures regarding my past life goals usually garner attention but my political stance gathers moss. The importance of my political thinking, I believe , far more important. We are on a precipice of subjugation. Perhaps the political climate of California OR the other Democratically controlled states are your want, But once instituted will be impossible to remedy. Beware, if that is your desire, Buy a ticket to Cuba, you’ll quickly learn that what you see as utopia isn’t, it’s squaller, A decadent way of life more akin to Somalia than the USA!