In the 1970s a consensus began to develop that House incumbents, all incumbents, were becoming safer. Given the context of American politics at that time – declining partisanship, increased ticket splitting, more office resources for members – it seemed plausible that incumbents were able to create more of a personal vote. It was a reasonable proposition that incumbents were able to increase their visibility and that more voters could be coaxed to support visible candidates, making it more difficult for challengers to do well versus incumbents.

The evidence, however, suggests there is much to doubt about whether the House has witnessed an increase in the incumbency effect. If there has been a change, it is in the ability of House Republicans to increase their vote percentages and achieve the status of being safe. There has been a significant partisan realignment in American politics that has put many more Republican incumbents in districts that their presidential candidates won. More Republican incumbents are running in districts amenable to Republican appeals, and that made increasing their incumbent vote percentages easier.

Evaluating and accepting this alternative interpretation will take some time. There will be critiques and counteranalyses. How we finally interpret the time period of the 1950s through now will not be resolved for some time. This analysis is essentially a first effort to present an alternative way of seeing the changes of recent decades, and there is much more to explore about how these changes have played out over time.