As I recall, the Teamsters endorsement
of Nixon was made in return for Nixon
releasing Teamsters' President
Jimmy Hoffa from Federal prison.

I think you're right--obviously this could not have been a quid pro quo out-in-the-open arrangement, but a deal cut by shady phone calls and under-the-table stuff as suggested by the Cooper character's campaign manager. The campaign manager's phone calls about the "dirty" tricks reminded me of Donald Segretti's (sp?) stories of the pranks he and a handful of others pulled on Democratic candidates.

.....And we haven't even gotten into the whole MAFIA talk that goes on between Columbo and his dentist!! Boy!!! this episode is chockful of controversy!!!!