Consistency makes an important contribution to trust. I think this is one of President Trump’s greatest issues. Consistency is easiest enough to evaluate given our present ability to check public positions because of recordings of various types and public access. Trump seems to function as if checking this consistency is not possible – what is said about topic A at time A is completely independent of what is said about topic A at time B; what is said in country A differs from what is said in country B. For example, the inconsistency of the complaints Trump made about Obama and Trump’s present behavior or statements. The phrases Trump insists other politicians use in this country and the phrasing he uses himself elsewhere. Trump complaining about such things encourages others (me) to evaluate you by your own standards.
Without consistency, you appear to be catering to the audience of the moment. Without consistency, it seems your positions are not truly held. Without a reasonable level of consistency, it is difficult to develop trust. People do change their minds and this is to be valued, but when such changes happen very frequently and without much in the way of logic or explanation frequent changes imply something else. Was it Kerry the Republicans attacked so relentlessly for being a flip-flopper? I seem to remember being consistent was once a Republican value. I guess times change and flipping on your own expectations for trust is sometimes necessary.