Some interesting articles on 1996 Boris Eltsin election, where Americans claimed their role in his win: 1 - http://articles.latimes.com/1996-07-09/news/mn-22423_1_boris... 2- http://content.time.com/time/subscriber/printout/0,8816,9848...
American political consultants != American intelligence agencies. When Trump retained a campaign manager with ties to Russian officials[0], it was a minor scandal, not something requiring over government response. [0] http://www.nytimes.com/2016/08/15/us/politics/paul-manafort-...
This is a very common thing to do this is what the diplomatic and intelligence services of most nations do all the time.