KABUL, Afghanistan (AP) — The stakes in Saturday's parliamentary elections in Afghanistan have never been higher, coming just two days after the Taliban assassinated two top provincial officials in an audacious attack on a security conference attended by the top U.S. military commander in the country.

The attack came just as Washington is trying to find a peace deal that will allow the U.S. to draw down its forces and extricate itself from the 17-year war, the longest in American history.

On Friday, Afghanistan's Independent Election Commission postponed polls in southern Kandahar province for...