Who's in charge in nuclear-armed US ally Pakistan?

Pakistan, a country that's critical to the U.S., Friday appeared to be sliding toward a judicial coup, in which judges are moving to oust top officials in the civilian government, but without putting the military, or anyone else, in charge. Courts summoned dozens of senior members of the ruling political party and were on the verge of issuing an arrest warrant for Interior Minister Rehman Malik as they followed up a landmark Supreme Court decision this week that nullified a legal amnesty that had shielded politicians from long-standing corruption charges. The U.S. relies on Pakistan for transit of most supplies NATO forces in Afghanistan and has pressed the government to crack down on al Qaida and Afghan militants who have sanctuary in the lawless border region, but top U.S. officials are playing down the crisis as an internal matter for Pakistan. Just who's running this nuclear-armed country of 165 million–the independent judiciary or another arm of the state–is unclear.