The major disagreement between Professor Tidmarch and myself is over different hunches about at what point in a congressman's career any incumbency advantage would show itself. We apparently agree on the accuracy of my conclusion that incumbency is only worth about two percent of the vote to first-term congressmen. But Tidmarch prefers to view the incumbency advantage as cumulative, increasing with each term the congressman serves, as he learns the ropes, gathers seniority, becomes more visible to his constituents, and perhaps eventually becomes accepted as an institution by them. If Tidmarch's is correct, the typical congressman might gain something like an additional two percentage points at the polls with each term of office he survives. For instance, a five-termer would gain about ten percentage points over his original victory margin, controlling for the partisan trend, rather than the mere two percent increase garnered in his first reelection attempt. Although Tidmarch's non-data based conjecture about a cumulative incumbency advantage contains a certain plausibility, it does not hold up under the scrutiny of some simple empirical tests that can be made with the readily available evidence. For example, my research note shows that when a congressman in the Fifties retired, the average loss to his party was only 2.2 percent of the vote beyond expected. Now, most congressional retirements (voluntary, via death, or a rare primary defeat) occur after several terms of office. Consequently, the minor two percent dip in the vote for a congressman's party when he retires reflects the impact of the loss of several terms of accumulated seniority, wisdom, seasoning, visibility, and prestige-not just one. Furthermore, contrary to Tidmarch's speculation, the vote margins of veteran congressmen do not improve markedly after their first reelection bids. For example, consider what happened to the 85 northern Republicans who sought at least their third term in 1952 and survived to contest the 1958 election. As these representatives gained the experience of an additional three terms, their average gain was only an additional 0.8 percent of the vote, controlling for the northern partisan trend.* Over the same period, the 36 northern Democratic veterans gained only an infinitesimal 0.4 percentage points beyond the northern