Retweets are Modern Day Pamphleteering
Politicians - whether they're party leaders or election candidates - are getting the heat for what they Retweet. Some folk say 'RT isn't important - it doesn't mean they back it'. Really? Imagine someone gave you a paper political pamphlet in the street saying these things. Then you gave them on - wouldn't recipients of these passed-on leaflets think they were your views, that - because you've given them time, they must have some significance to your own views (unless you merely quoted them in a new pamphlet which is itself a condemnation of them say).
(Image of pamphleteer from Wikipedia)
Thomas Paine's leaflets were influential in the US War of Independence. Similarly, they featured in the English Civil War and the French Revolution, and much else besides:
RTs are modern day pamphleteering - they're not a passing whim of no consequence and no meaning regarding your own views.