Three factors related to the american electoral system affect who is elected to office in this country, and what they do once they get there. those factors are…

Factor 1:  Who decides to run for office and what advantages candidates have over one another.

Factor 2:  Incumbency.  Usually the incumbent (the person already serving in the office) has a large advantage over challengers, unless negative events have the voters wanting to get rid of incumbents.

Factor 3:  The way congressional districts are drawn.  There have been court cases recently about "gerrymandering" -- attempts by a party in power to draw district boundaries in ways that will serve to perpetuate that party's power.