Well, i have some experience in the issue, although I'm from a small european country you've probably never heard, I am in the middle of forming my own political party. I've studied many issues about this extensively, and what i realized (and i think everyone knows this deep down) is that a politician will only do the necessary amount of good so he can get reelected. maybe they pass a civil rights bill, maybe they make some random environmental reform etc. Some of the time they don't even do good so they can get reelected, they just try to pass some shitevil bill "sponsored by" (meaning = bribed) companies, and to do that they include some reforms so they can market it well. The only thing most politicians care about is money and power. nearly nothing else.

I can talk about this topic for hours, and it still won't be enough, but in short: power hungry people will aim to be politicians, and lying is a very strong weapon to have. so if 10 same talented people aspire to be politicians, and 5 of them are sociopathic liars, 5 of them are honest, then the 5 liars will have an insane amount of advantage. So this process repeating for many many years, honest politicians disappeared from our life to the point that we ACCEPT that politicians lie. Before internet we had obviously no CHANCE to find out anything about our presidents. but times have changed, we have internet, we can search for videos in 3sec about how huge lies politicians did. So don't in your life should you accept that a politician SHOULD lie because it worked out so far. it was IMPOSSIBLE before to elect a honest president unless he was fucking albert einstein and jesus in one person.

So don't believe a word any president said before, there are VERY few exceptions. Mainly after big revolutions when people were truly motivated because they felt they did something good. but human nature is not fit to do politics as it is right now. they will get insanely corrupt due to the environment. (if you are interested about topic, Dan Ariely has some interesting and relatively short videos about these topics and human nature in general)

The only real choice USA has is Sanders. he is not perfect, he has some weak ass typical socialist ideals (like let in all immigrants without any border control), which actually don't work because they are too naive, but he is a HONEST politician. if people start to finally vote for HONEST people, then more clever and not naive honest people will pour in very fast. YOU need to take the first step and not just wait for a perfect knight in shining armor to help you and your country. Politicians/people can change their economic/sociology strategies, but they cannot change their personality. if someone is a lying psychopath, he will be a lying psychopath till the end. (but on another note, trump probably is not THAT bad as leftists might think. I don't have enough information about him to know for sure. all i know is all other republican candidates are literally cancer, and we shouldn'T even talk about hillary, who is the same psychopath as any other politician... although still better than most republicans)