A curious ambiguity arises when a negative main clause is followed by a ‘because” subordinate clause. Look at the following sentence:
Leaders of the Islamic State don’t want Donald Trump to lose because they like him.
Do you see the ambiguity? Take a minute to think about it and say the sentence out loud. The ambiguity is easier to spot in the spoken language because of intonation. As the sentence stands, there are two possible and completely opposite meanings.
Meaning one: The leaders of the Islamic State do like Donald Trump, and that’s why they don’t want him to lose.
Meaning two: There is some reason other than liking Donald Trump that makes leaders of the Islamic state not want him to lose.
You will immediately see meaning two if the real reason is given in a subsequent sentence:
Leaders of the Islamic State don’t want to see Donald Trump lose because they like him. They hate him, but they think his plans to close down mosques and register American Muslims will do the most to advance their agenda.
So the sentence has to be revised.
Meaning one: Leaders of the Islamic State want Donald Trump to win because they like him.
Meaning two: Although they hate him, leaders of the Islamic State want Donald Trump to win.