Nawaz Sharif, a veteran of Pakistan’s political tumult

CNN’s Jethro Mullen weighs in on Nawaz Sharif

The strongest contender to become the next Pakistani prime minister is hardly a newcomer to the country’s political stage.

Nawaz Sharif, 63, has had a long and rocky career that includes two stints as prime minister during the 1990s, ordering Pakistan’s first nuclear tests, a showdown with the nation’s powerful military, time in jail and years of exile.

After spending the past several years in opposition to the governing Pakistani People’s Party (PPP) — which has struggled to tackle the country’s crippling problems of militant violence, chronic power shortages and a flagging economy — Sharif now has a shot at another stint in office.

But observers say his positions on key issues such as Islamic extremists and relations with the United States remain vague, raising uncertainty about what kind of approach he would take if his Pakistani Muslim League Nawaz (PML-N) were to succeed in forming a government in the national assembly following general elections this weekend.