Where politicians are concerned, verify, I repeat, verify everything they say. Make sure their actions match their promises. If they don’t, fire them at the next election.
A corollary of the counsel above. Candidates are not in the business of helping their opponents get elected. Their claims about their opponents will be one of only two possibilities: misrepresentations or just plain lies. We saw this in spades during the recent primaries.
If they play fast and loose with the truth, do not show any respect for opponents or their supporters, engage in unethical and even immoral conduct during the campaign, then imagine that they will act similarly while in office.