It's [reported this week][1] that "Trump aides were in constant touch with senior Russian officials during [the presidential] campaign".

In the CNN article linked above, it states that it's not unusual for a campaign staff and representatives to communicate with foreign governments.

> Officials **emphasized that communications between campaign staff and representatives of foreign governments are not unusual**. However, these communications stood out to investigators due to the frequency and the level of the Trump advisers involved. Investigators have not reached a judgment on the intent of those conversations.
>
> *(emphasis mine)*

So, is this unusual? Have there been precedents of other campaigns in the past that communicated with foreign governments **during the election campaign**?

**Non-opinionated answers with sources are appreciated.**


  [1]: http://www.cnn.com/2017/02/14/politics/donald-trump-aides-russians-campaign/index.html
  [2]: https://en.wikipedia.org/wiki/Logan_Act