Why did the writers of the constitution decide to use electors instead of relying on the popular vote?

So that all states have a somewhat equal amount of say in elections, because depending on only the popular vote would mean that smaller states with a lower population would barely be able to influence elections.

nothing certain is known about what happened, but it seems that the country declined gradually, perhaps due to bad government, or, more likely, due to a series of bad harvests, which resulted in widespread and recurrent famine.

powers  are  denied  to the  national governmentin three distinct ways: some  powers, such as the  power  to levy duties on exports or prohibit the freedom of religion, speech, press, or assembly, are expressly  denied  to the  national government  in the  constitution.