Pakistan President Pervez Musharraf's "coup against his own government" puts his main backer the US in a spot, where even the best-case scenarios are messy if not dangerous.
Mr Musharraf's crackdown, despite strong US entreaties, drives home the price Washington is paying for backing a wayward ally in the war on terrorism, while overlooking failures of performance, capacity and will, experts said on Sunday.
US pressure on the military strongman who took power in a 1999 coup, to take steps toward restoring democracy and civilian rule came too late to advance American goals, they said.
Mr Musharraf imposed emergency rule on Saturday in a bid to reassert his flagging authority against challenges from Islamist militants, a hostile judiciary and political rivals.
As opposition figures were rounded up in a nationwide crackdown that continued on Sunday, US Secretary of State Condoleezza Rice said the US would review billions of dollars in aid - in part because US laws set conditions for some military aid.
Politicians called for tougher US actions. "We have bolstered Mr Musharraf with billions of dollars in recent years in military support and we ought to be specific that it's not going to continue," said Pennsylvania Republican Senator Arlen Specter, a senior member of the Senate Appropriations Committee.
"And then on the terrorism front with al Qaeda and Taliban having control in provinces we have to give some consideration to perhaps some unilateral action," he said on CNN's Late Edition.
Republican presidential candidate Fred Thompson called for a "hardball" approach with Mr Musharraf short of cutting aid that also recognised the high stakes at play in Pakistan.
"We need to understand that this is a nuclear country," he said on NBC's Meet the Press.
We could face a real nightmare scenario by seeing these radical elements, these terrorist sympathisers, take control of that government," warned Mr Thompson.
Pakistan this year is receiving about $700 million in US economic and military assistance and next year is expected to receive more than $800 million. The country has received about $10 billion in US aid since 2001, with much of that in counter-terrorism assistance.
Retired US diplomat Teresita Schaffer said Washington's scope for action beyond tactical steps to show displeasure at Musharraf was narrow, in a country that borders Afghanistan - another US ally at war with resurgent Islamic militants.
"We don't have the luxury of simply blowing off the whole country," the South Asia expert at the Centre For Strategic and International Studies think tank told Reuters.
"Strategically, we have to work with whoever is in charge of Pakistan," she added.
US legal structures against giving military aid to countries after army coups could be finessed by deciding they don't apply to a Pakistan with "the same guy in charge, albeit under very different circumstances," Ms Schaffer said.
She predicted Washington will continue aid "and those aspects of military assistance and coordination that are specifically related to anti-terrorism and to Afghanistan".
Pakistan's army has been playing a "double game" in joining hands with the US and taking aid yet not fighting the Taliban and other extremists with sustained vigour, said Brookings Institution analyst Stephen Cohen.
"In effect we've wasted several billions of dollars, becoming Mr Musharraf's ATM machine, allowing him to build up a military establishment that was irrelevant to his and our real security threat, yet presiding over an intensification of anti-American feelings in Pakistan itself," he wrote in a soon-to-be published essay for the website www.brook.edu.
Emergency rule will not help reach US anti-terror goals. "Mr Musharraf's recent coup against his own government - for that is what it was - does nothing to improve the Pakistan army's performance in matters of vital concern to the US," wrote Mr Cohen.
He sees a best-case scenario of carefully controlled elections bringing former Prime Minister Benazir Bhutto back into office, to work with an army run by trusted Musharraf advisers in fighting extremists.
But that picture is clouded by fears that Mr Musharraf's men will reject Ms Bhutto and extremists won't give up on their drive to "turn Pakistan into a base from which they can attack other soft Muslim and Western states and India, and even lay their hands on Pakistan's nuclear arsenal," he warned.