An alternative way to paraphrase the sentence given is:
<em>"The candidates debated if the current policies were appropriate due to changes in the economy, shifts in the population, and end of war.</em>
In this case, the use of parallel structures helps make the sentence more coherent by using the same grammar patterns. The grammar pattern is <em>noun+prepositional phrase</em>:
A new sentence with more appropriate choices would be “<em>The candidates debated whether the current policies were appropriate, since the economy had changed, there were shifts in the population, and the war had ended.</em>”. The changes made in the sentences were:
* I<u>ntroduction of the conjunction “whether”</u> involving alternatives, together with the verb “<em>debate</em>” that has this meaning.
* I<u>ntroduction of the conjunction “since”</u> with the meaning “<em>in view of the fact that</em>” or “<em>because</em>”. This is so to give reasons to the debate (“<em>the economy had changed, there were shifts in the population, and the war had ended</em>”).