Pakistan banned protests in its largest province and opposition parties claimed their members were being arrested Wednesday ahead of planned rallies threatening to batter the already-shaky rule of its pro-Western government. The political crisis comes as the nuclear-armed country is grappling to contain surging violence by al-Qaida and the Taliban and fix an economy that remains functioning only due to support from international lenders. It could lead to political meltdown and even some form of intervention by the country's powerful military, which have often seized power in the past following chaotic civilian rule. The turmoil erupted last month when the Supreme Court banned the head of the largest opposition party, Nawaz Sharif, and his brother, from elected office. They accused President Asif Ali Zardari of engineering the verdict to neutralize them.