First and foremost, everything they say and do is carefully calibrated toward getting re-elected. If they feel that disclosing the truth will lose votes, they will not tell the whole truth and will either lie outright to their constituents or obfuscate the facts in such a way as to protect themselves.
Leaders tend to say what they would like to happen, not what will or can happen.
Leaders tend to bend the interpretation of facts to make them look good.
Some leaders appear to have no regard for the truth at all, and are even out to change the meaning of the truth.
I think we all lie to some degree. Usually to get something we want, or to avoid shame. Leaders are just like us, only more so. Plus, we are all leaders at some level.
They think the truth will be unpopular. And they are more concerned with being popular than in doing what is right.
To promote their ideas.
He is delusional and thinks he knows everything so he really doesn’t think he ever lies, because he said it.
Leaders lie because they don’t truly believe what they stand for, and they know that others won’t stand for what the leader truly believes in.
There are probably some cases where not telling the truth serves some better purpose. Perhaps the truth would create more serious issues or be difficult for others to accept. I think that some lie because they were brought up to think that lying is an acceptable form of behavior.
They say what they think you want to hear in order to gain your support.
Telling the truth on a particular matter may have serious negative consequences.
It may sometimes be necessary to lie, e.g. in matters of national security.