Why have congressional incumbents enjoyed a 90%re election rate since the late 1940: The national status of an incumbent's party influences voters,
Voter apathy tends to favor incumbents when voters go to the polls
Voting restrictions tend to favor incumbento,
It is easier for incumbents to raise funds from their own districts,
Voters may believe an incumbent best represents their views
Voting patterns are driven by media bias
incumbents count on grateful voters whose problems they have solved
Incumbents are better known to voters
Many districts have been gerrymandered in favor of the incumbent