One of the most widespread and popular theories is that the powers and perks of incumbency in Congress, which have grown exponentially in the past two decades, have created a situation in which incumbents cannot be beaten except in the most extreme circumstances. . . . Proof for this contention comes from the astonishing success rates for incumbent House members, particularly in the last two elections (98 percent and 98.4 percent, respectively). . . .
There can be no doubt that incumbency provides enormous advantages; it at least partially explains the phenomenon of Democratic one-party control. At best, however, it is an incomplete explanation. To begin with, re-election rates for incumbents have been high for more than a century, and have averaged more than 90 percent for several decades at least; they changed little with the expansion in incumbent perquisites or the alteration of campaign financing. . . .
If the incumbency theory holds true, there should be many seats previously held by Democratic incumbents that go over to the Republicans when the incumbents leave those seats-and many fewer seats held by Republican incumbents going over to the Democrats when those seats open up. But the reality is the opposite. . . . Since 1954 Republicans have won 77 open Democratic seats in the House of Representatives; Democrats have won 101 open Republican seats.
