Backing a candidate and promoting him is not propaganda. Backing a non candidate by posting lies about a running candidate,in order to drag him down so your candidate, who is not running can somehow reap the benefits is more along the lines of propaganda. Other examples are 2 hour movies like “Undefeated” and your candidate actually has the benefit of acting like an honest broker as a paid commentator for Fox where she spend that time bashing the Republican field, namely Perry.
When you are consistently shilling and flacking for a candidate and posting debunked myths/falsehoods and revisionist history (or outright lies), that most certainly is propaganda.