The Taliban have rejected the April 5 election and have already stepped up attacks to sabotage it.
The militants will also be looking to capitalise if the vote is marred by rigging and feuding between rivals seeking to replace President Hamid Karzai who cannot run for a third term under Afghan law.
Whoever replaces him will inherit a country beset by deepening anxiety about security as most foreign troops prepare to pull out by the end of the year, leaving Afghan forces to battle the insurgency.
Monthly attacks in Kabul, where candidates are expect to focus their efforts to win over women and young people, are at the highest since 2008, one embassy said in a recent security report.
"This increase can be attributed to efforts towards the presidential elections," the embassy said.
Many Afghans say they are taking precautions. While the country has no majority community, ethnic Pashtuns are considered the largest community and ethnicity will play a big role in deciding the next president.