Pakistani President Asif Ali Zardari and his ruling party have thrown down the gauntlet in the face of calls for him to resign, condemning what they called a witch-hunt and vowing to foil conspiracies again them.

Opposition politicians and hostile sections of the media have called for Zardari to resign since the Supreme Court on Wednesday struck down an amnesty that protected him and others from corruption charges.

The tension comes as the United States has been stepping up pressure on Pakistan to go after Afghan Taliban factions in enclaves on the Afghan border, while homegrown militants have been unleashing carnage with a series of bomb attacks.

Here are some scenarios for how the trouble might play out:

MILITARY INTERVENTION

The chance of military intervention at this stage is seen as extremely remote. There is no speculation in Pakistan about a military coup despite rumours in foreign exchange markets in Asia early on Friday, apparently sparked when the defence minister was not allowed to leave the country on the orders of the state anti-graft agency. The minister was on a list of people protected by the 2007 amnesty which the Supreme Court struck down.

The army has had its differences with Zardari, in particular over a U.S. aid bill critics said violated Pakistani sovereignty. But the differences are not seen as serious enough to justify a coup by an army wary of getting involved in politics so soon after the restoration of civilian rule. Army chief General Ashfaq Kayani has vowed to stay out of politics and he played an important role in March in the restoration of a Supreme Court chief whom former president Pervez Musharraf sacked in 2007.

That same chief justice will now oversee proceedings against politicians and bureaucrats who could face prosecution. The judiciary has wide public support while investors have been encouraged by the Supreme Court’s rejection of the amnesty, which is seen as improving transparency.

ZARDARI RESIGNS

Zardari is not expected to step down any time soon. He has always struggled to match the popularity of his charismatic late wife, Benazir Bhutto, and has been dogged by accusations of corruption stemming from her terms in power in the 1990s. He says the charges were politically motivated and he has never been convicted. He is also safe from prosecution because of presidential immunity.

Some opposition politicians, mostly from the party of former prime minister Nawaz Sharif, and sections of the media have been calling on him to resign but he has dismissed the calls. He met top leaders of his party on Saturday and they vowed to fight enemies and foil conspiracies with “democracy and constitutionalism” as their weapons.

Even if Zardari were eventually to resign, his ruling Pakistan People’s Party would remain in control of the government and would likely determine who would become the new president, who is elected by parliament and provincial assemblies.

SO WHAT HAPPENS NEXT?

Pakistan’s latest political troubles will play out in the courts, not on the streets. Four ministers, including the defence and interior ministers, were on a list of people covered by the now defunct amnesty and could face legal proceedings. They could eventually resign but their departure would not have a big impact on the war on militancy, which is led by the army.

The danger for Zardari is that the legitimacy of his 2008 election as president could be challenged now that old cases against him have been revived. Much will depend on how aggressive the courts are in going after him. Opposition leader Sharif could call protests against Zardari although he has said he does not want to “derail” the democratic system. He has not called for an early general election but his party is expected to do well in the next polls, due by 2013.

IMPLICATIONS FOR THE WAR ON THE TALIBAN

Political turmoil will divert government attention from the fight against militants, to the dismay of the United States. Pakistan’s effort to tackle the Afghan Taliban is critical to U.S. aims in Afghanistan. Ties have been strained by Pakistan’s reluctance to heed U.S. pressure to crack down harder, with Pakistan officials saying they cannot move too fast without provoking a backlash against Zardari. The militants can be expected to capitalise on the uncertainty and step up attacks. (REUTERS)