These questions are broad enough to invoke a macro and micro answer, if read without bias or pre-conceived notion.   

The macro answer is they, being the invaders, work in many ways -- but one is via the manipulation of education and the undermining of a healthy, reproductive society.  

One  way to undermine a society is to tell children in that society that laws don't matter while failing to sternly discipline children for unethical and illegal behavior at a young age.  Children who grow up with vague or absent moral, ethical and legal guard rails  are without clear delineations between right and wrong -- and they  produce children who do the same.  By the end of the 2nd generation or beginning of the 3rd, no matter the rules and laws of a society, none are respected, and not even by those paid to enforce them.  Charlotte Iserbyt is a person who spoke of these concepts and she wrote a book called the "Dumbing Down of America".  

Another way is via sexual perversion.  Both heterosexual and homo sexual. Not limited in scope. 

An example of the micro answer is below. 

** - full disclaimer up front -  The publisher of this content believes there is a j--ish supremacy problem in the United States and around much of the world.  However, it also remembers that it was Royals of Europe (and possibly elsewhere)  who often employed them to handle usury matters, because, somehow, they felt that would excuse them from responsibility without credibility.  This website and content focuses more on the Hidden Royals than those employed by them for usury services -- but that is not meant to discount obvious concerns during rapidly changing times.  If this perspective is  perceived as a "publishers bias",  "racist", or a "concern for you",  the reader,  there are a gazillion other publishers you can choose to spend your attention on.  These facts are not open to debate.  It was Rome and prior, back to Carthage and maybe even Sumeria that attempted to pursue righteous Republics,  and others who constantly sought to subvert them.