The use of nomina propria in adverbial position after verbs that normally govern a postposition is a fairly recent innovation in American media language, derived no doubt from the language of advertising (shop Gucci, ski Bromley). Eliminating the postposition (i.e., lean Democratic instead of the orthoepic lean toward the Democrats) is stylistically colloquial, consonant grammatically with the greater immediacy of transitivity vs. intransitivity.

Those speakers who use such locutions may or may not be motivated by the goal of a certain stylistic rakishness, but what this violation of collocation rules confers on phrases like leaning Obama and voting Romney in any event is the impression of greater closeness to the topic of discourse––here, the political fray––when compared with their normative syntactic equivalents.