Summary: This article from The New York Times is reporting that Donald trump has changed his very firm status on immigration, only to change it back a few hours later. Donald Trump's big statement, from the start of the campaign, the big policy he has stood by, is that all illegal immigrants need to be deported. Mr. Trump paid a visit to Mexico city, where he said he had tremendous respect for the Mexican people, and he would focus on deporting only the most dangerous immigrants, a plan that current president Barack Obama has been attempting to enforce. However, he then gave a speech in Phoenix, Arizona that same day, that portrayed illegal immigrants as a threat to society, that Hillary Clinton's plan was to open the borders, and that America should deport her. Mr. Trump has changed many other of his policies many times, and has told many different groups many different things.
History connection: Inconsistencies are rife within presidential campaigns. Sometimes it's because of new developments, but most of the time, it's because the candidate makes a promise that the public wants to hear, without telling the public if its feasibly possible. For example, George W. Bush made a promise of no new taxes, but raised taxes all the same when he got into office.
Question: Why do presidential candidates make promises they can't keep, and when called out on these impossible promises, why do people still vote for them?