I always thought Richard Nixon would have made a first-rate SecState. International relations were always his primary focus, and he knew when to get tough and when to back off.
There are times when I still shake my head over the election of Spiro Agnew. It took a split Dem party in MD to get him to the governor's chair in the first place. And then it took the last brokered convention of the GOP to get him as a "well, OK, if you insist..." compromise candidate, and the Dems to splinter badly among Wallace, Lyndon Johnson, and George McGovern (what did he get: maybe 37% of the popular vote and about 280 electoral votes?). He was to the GOP what Lyndon Johnson was to the Dems: a wheeler-dealer, just barely not on the shady side of the law.