When a country depends on an ally to provide heavy lifting in a war, any hint of instability makes people understandably nervous.  That’s even more true in the Afghanistan-Pakistan theater, where the US has pressured Pakistan’s government to get more aggressive in attacking Taliban and al-Qaeda locations in the north.  Until now, the government has at least supplied some military pressure — but the most aggressive action has come from the courts, which reinstated corruption charges against thousands of politicians, including high-ranking allies of the US:

A sweeping Supreme Court decision that re-opened corruption cases against thousands of politicians, including President Asif Ali Zardari, reverberated through the government Friday, as key ministers were barred from leaving the country and ordered to appear before the courts in the coming weeks.

Among those immediately affected were the interior minister, Rehman Malik, who is considered particularly close to the United States, and the Defense Minister, Ahmed Mukhtar, raising concerns about how effectively the Zardari government, under pressure from a violent Islamic insurgency, could continue to function.

The two men were among 247 officials, also including placed on what is known as an exit control list, barring them from leaving Pakistan, a measure Pakistan authorities often use to ensure those under criminal investigation do not abscond.

At least 52 politicians, also including Salman Farooki, the chief of staff to Mr. Zardari, who were called to appear before corruption courts, according to the National Accountability Bureau, the anti-corruption unit that was ordered by the Supreme Court Wednesday to act expeditiously in re-opening the cases.

The man at the heart of this decision is Chief Justice Iftikhar Mohammed Chaudhry, who got fired by Pervez Musharraf and whose termination set off a popular effort to push Musharraf out of power and restore the judiciary.  Chaudhry overturned Musharraf’s grant of immunity, which also applied to Musharraf himself, which the former dictator had granted as a means to allow most politicians to return to politics.  Corruption has been rampant in Pakistan, but anti-corruption prosecutions have been corrupted by political vendettas as well.

Zardari himself cannot be prosecuted, as his office grants him immunity.  However, his political opponents want him to resign and face the charges as well as dismiss those in his government in the same position.  Zardari has thus far refused to do so, pitting him against those less sympathetic to the West and more sympathetic to the Taliban and their allies.

That may also create problems with the Pakistani Army.  They have not been shy about seizing power when they sense weakness in the civilian government, and they’re already unhappy with Zardari.  They find him too conciliatory towards Pakistan’s traditional enemy India, and ironically resent his attempt to reform the intelligence services by appointing a civilian to run it.  If Pakistan turns into a mess, then the army will likely seize power — and that will probably spell an end to most of the cooperation between Washington and Islamabad.