Disclaimer. Don't rely on these old notes in lieu of reading the literature, but they can jog your memory. As a grad student long ago, my peers and I collaborated to write and exchange summaries of political science research. I posted them to a wiki-style website. "Wikisum" is now dead but archived here. I cannot vouch for these notes' accuracy, nor can I even say who wrote them. If you have more recent summaries to add to this collection, send them my way I guess. Sorry for the ads; they cover the costs of keeping this online.
Burden. 2002. United States Senators as presidential candidates. PSQ.
Despite the popular view of Senators as natural presidential candidates, Senators do a remarkably poor job of capturing their party's nomination and winning presidential elections. Governors, on the other hand, fare much better. These results are statistically significant. Burden spends the bulk of his paper considering four possible explanations for these findings.
Senators are constantly forced to declare their positions on roll-call votes. Governors, on the other hand, can set their own agenda and can remain strategically ambivalent. Moreover, success in the Senate requires lots of negotiation and few opportunities for credit-claiming; success for governors, on the other hand, providers clearer policy outcomes to take credit for.
Though we might think there are more Senators (100) than governors (50) who can run for the presidency, we must examine former office holders--and there are surely far more former govenors (due to term limits) than former Senators. Thus, there is a bigger pool of former governors than of former Senators, so it makes sense that there might be better potential candidates among (former or current) governors than among Senators.
Clearer connections to the investment and ambition theory.
Research on similar subjects