A year after an election returned Pakistan to civilian rule the country has slid back into a political crisis, with street protests erupting and more planned.
The timing, as usual in Pakistan, is awful as new concerns have arisen about the ability of the nuclear-armed U.S.-ally to stem a rising tide of Islamist militancy after last week's attack on the Sri Lankan cricket team.
Meanwhile, the economy is being propped up by the International Monetary Fund but needs more external support.
The last thing Pakistan needs is political turbulence so soon after former army chief Pervez Musharraf was forced to resign as president last August.
HOW DID THIS CRISIS ERUPT?
The Supreme Court last month effectively barred former prime minister Nawaz Sharif and his younger brother Shahbaz Sharif, who are opposition leaders, from contesting elections.
Shahbaz Sharif's victory in a by-election last year was nullified, and he was disqualified from holding office as chief minister of Punjab, the most populous and 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 Sharifs' Pakistan Muslim League (Nawaz) (PML-N).
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.
Bhutto's Pakistan People's Party (PPP) and the Sharifs' party were bitter rivals in the 1990s, a turbulent decade in which Bhutto and Sharif both served as prime minister twice without completing a term. A military coup in late 1999 ousted Sharif and brought Musharraf to power.
Analysts fear a return of the politics of confrontation between the country's two biggest parties.
Opposition to Zardari is coalescing around a demand for an independent judiciary, with the PML-N and other opposition parties set to join anti-government lawyers in a cross-country protest beginning on Thursday and due to reach Islamabad on March 16. The "long march" protest aims at securing the restoration of a former chief justice of the Supreme Court, Iftikhar Chaudhry, sacked by Musharraf in 2007.
Zardari fears if Chaudhry is reinstated, he could nullify an amnesty Musharraf granted Bhutto and Zardari to enable them to return to Pakistan without fear of prosecution on old charges of corruption.
The parties vow to mobilize their support and protest organizers plan a sit-in outside parliament in Islamabad from March 16. Clashes are likely if police try to block the protest.
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 for more than half Pakistan's 61 years of history, will feel forced to act.
The army has little reason to back Sharif, even if Zardari is widely unpopular and disliked by hawkish elements who distrust his pro-West stance and dovishness toward India.
Sharif had bad relations with at least three army chiefs during the 1990s. Moreover, the West is wary of Sharif, believing he panders to the religious/nationalist constituency that opposes the war on terrorism.
The United States wants Pakistan to focus on fighting the Taliban and al Qaeda, and doesn't want the army diverted by politics or, analysts say, drawn into helping Sharif.
Beleaguered stocks and the rupee, which both fell sharply last year, have been under pressure from political worries.
ANY CHANCE OF RECONCILIATION?
Some politicians, including coalition partners, have tried to mediate, but a leader of Zardari's PPP said on Sunday there was no chance of reconciliation.
Both Sharif and Zardari covet Punjab -- politicians say whoever controls the province that returns more than half the members of the National Assembly controls the country -- but neither has a clear majority in the provincial assembly.
The balance of power lies with Pakistan Muslim League Quaid-e-Azam (PML-Q), carved out of Sharif's party by Musharraf to back his rule.
(Writing by Zeeshan Haider and Robert Birsel; Editing by Jerry Norton)