By Mark Urban
BBC Newsnight Diplomatic editor
US officials regard Wednesday's meeting between President Barack Obama and the leaders of Afghanistan and Pakistan as an important diplomatic landmark.
The talks come at a time of increasing Taleban activity in the region
The emphasis on combating militancy is a key part of Mr Obama's foreign policy - some indeed would say it is the central issue of it.
The Washington meeting, though, has brought to the surface all kinds of tensions about the Obama approach.
A defiant, bellicose upland people have already made their anger felt - I'm referring to the US Congress.
During Tuesday's hearings on Capitol Hill, Richard Holbrooke, the administration's "Af-Pak" envoy, came under fire from Congress men and women who believe America's aid to Pakistan looks too much like a blank cheque.
They want "conditionality", linking the flow of dollars to Pakistani co-operation on everything from fighting the Taleban, to reining in the ISI (the country's military intelligence organisation), securing nuclear weapons and gaining access to AQ Khan, the scientist accused of proliferating nuclear technology to several countries.
The US gives Pakistan around $2bn each year in military aid and is now increasing its civilian aid package to $1.5bn annually.
Mr Holbrooke accepted that performance benchmarks are required
Over the next five years US aid could total $17.5bn, and help from international financial institutions another $14bn.
During Mr Holbrooke's session he came under fire both from congressmen like Ron Paul, who expressed broad doubts about the wisdom of the new US strategy, to others like Robert Wexler, who are closer to White House thinking but want guarantees about the spending of US funds.
Mr Holbrooke said the administration did not believe in conditionality but accepted that benchmarks are required to measure Pakistan's performance.
Whether or not the US aid is linked to specific yardsticks, many Pakistani officials find the approach patronising.
Since those who believe in co-operating with the US are already characterised by the opposition as foreign hirelings, the conditionality policy might offer further political ammunition to the militants.
'Inept counter-insurgency efforts'
If Congress is reluctant to bankroll Pakistan unconditionally, their decision stems in part from the experience of the past five years.
Mr Zardari has emphasised the values shared by Pakistan and the US
Despite billions invested, the Pakistani army remains inept at counter-insurgency operations, causing large civilian loss of life and suffering high casualties of its own.
As for other issues, even Mr Holbrooke described the refusal of the last Pakistani government to let US agents interview AQ Khan as "inexplicable".
From the Pakistani side, the government was nettled at being called "fragile" by Mr Obama. It feels also it must reflect public anger about US air strikes in the tribal areas - although Pakistan actually facilitates these attacks in various ways - and it regards US pressure to confront the militants militarily as unwarranted.
At a US State Department session with Hillary Clinton on Wednesday, Pakistan's President Asif Ali Zardari placed great emphasis on the democratic values shared by Pakistan, the US and Afghanistan.
And in truth democracy and sovereignty may provide Pakistan's best counterweight to those Americans who call for conditionality of aid.
Talking to the Taleban and attempting local truces are after all policies that the dominant political party in the tribal areas ran on during last year's elections.
US pressure for military responses in these places, it can be argued by Mr Zardari, flies in the face of the people's will.
Mark Urban's full report on the Obama administration's 'Af-Pak' strategy was broadcast on Newsnight on BBC Two on 6 May 2009.