Q+A - Crisis in Pakistan; What's happening this time?

By Zeeshan Haider and Simon Cameron-Moore

ISLAMABAD (Reuters) - A year after an election returned Pakistan to civilian rule the country has slid back into a political crisis, with street protests erupting in towns and cities across central Punjab province.

The timing, as usual in Pakistan, is awful.

The new U.S. administration is conducting a regional review of its strategy in Afghanistan and Pakistan for defeating al Qaeda and the Taliban.

There are worries the Pakistan government is too ready to appease militants, after a peace deal worked out in a northwestern valley earlier this month.

Meantime, the economy has been propped up by the International Monetary Fund, but needs more external support.

The last thing Pakistan needs is a power struggle, so soon after former army chief Pervez Musharraf was forced to resign as president last August.

HOW DID THIS CRISIS ERUPT?

The Supreme Court on Wednesday effectively barred opposition leaders, former prime minister Nawaz Sharif and his younger brother Shahbaz Sharif, from contesting elections.

Shahbaz Sharif's victory in a by-election last year was nullified, and he was disqualified from holding the office as chief minister of Punjab, the most populous and most influential of Pakistan's four provinces.

President Asif Ali Zardari, husband of the late Benazir Bhutto, then went a step further.

He imposed central rule, known as governor's rule, in Punjab for two months, and threw out the provincial government of the Sharif's Pakistan Muslim League (Nawaz) (PML-N) faction.

The Sharifs and the PML-N, Pakistan's second-largest party, have accused Zardari of being behind the court decision. Their supporters have taken to the streets and more strife is expected.

WHAT'S AT STAKE?

Pakistan's latest attempt at democracy is at risk.

Musharraf's successor as army chief, General Ashfaq Kayani, has vowed to keep the army out of politics. But, the danger is that if the crisis becomes acute, the military, which has ruled Pakistan for more than half of the country's 61 years of history of independence, could be forced to act.

ANY CHANCE OF RECONCILIATION?

Some politicians, including smaller allies of Zardari, have offered to mediate, but chances of reconciliation are remote.

Both Sharif and Zardari covet control of Punjab, but neither has a clear majority in the provincial assembly.

The balance of power lies with Pakistan Muslim League Quaid-e-Azam (PML-Q), which was carved out of Sharif's party by Musharraf to back his rule. PML-Q politicians are being wooed by both sides to form a government once governor's rule ends.

WHY DOES SHARIF THINK ZARDARI FIXED THE COURT RULING?

Nawaz Sharif has committed his party to supporting the lawyers' movement trying to force Zardari to reinstate a Supreme Court chief justice, Iftikhar Chaudhry, who was suspended and later dismissed by Musharraf in 2007.

Zardari fears if Chaudhry is reinstated, he could rule that Musharraf's re-election as president in 2007 was invalid and also try him for violating the constitution by declaring emergency rule in November that year.

Chaudhry could then nullify the amnesty, known as the National Reconciliation Ordinance, that Musharraf granted Bhutto and Zardari to enable them to return to Pakistan without fear of prosecution for old charges of corruption.

Dozens of judges ousted by Musharraf have returned to the courts, but not Chaudhry.

WHAT'S THE HISTORY BETWEEN ZARDARI AND SHARIF?

Bhutto's Pakistan People's Party (PPP) and the Sharif's PML-N had daggers drawn throughout the 1990s, a turbulent decade in which Bhutto and Sharif both served as prime ministers twice without ever completing a term.

The decade ended with a military coup in late 1999 that ousted Sharif and brought Musharraf to power.

Bhutto had already gone into exile to escape drowning in corruption cases against her. Zardari joined her in exile after being released from prison in 2004. He was never convicted of any crimes he was accused of, but his reputation was tarnished.

Musharraf had banished the Sharifs after first having them convicted of crimes. In Nawaz Sharif's case he was found guilty of hijacking the airliner that brought Musharraf home from an overseas trip on the day of the coup.

When the PPP won the election last year and PML-N came second, Zardari enticed Sharif into a coalition government with a promise to quickly restore Chaudhry and the other judges. Sharif pulled his ministers out of the government within weeks once it became clear Zardari was dragging his feet.