Today (26th of June 2018), the SCOTUS decided that the Sept. 2017 Executive Order banning travelers from several predominantly Muslim countries from entering the United States (the "Travel Ban") does not violate the 1st Amendment of the US constitution. Notably, the SCOTUS declared that the campaign promises that the President made during his campaign rallies of banning all Muslims from entering the country (paraphrasing here) should not be taken into account when deciding whether this order is violating the 1st Amendment.
As someone who doesn't live in the USA and isn't a constitutional lawyer, I don't really understand that. If I say "I'm going to kill the guy who slept with my wife" and 3 days later I jump out from behind a tree and kill him, that's considered premeditation, which increases the severity of the murder charge. However, if the President says "I'm going to ban all Muslims" and then a year or so later does something to that effect, why is it not taken into account?