United States President Barack Obama’s insistence that NATO, not the United States, take the lead in attacking Muammar Gaddafi’s military is exposing a hard truth about an alliance that never before fought an air campaign with the US in the back seat. Even against an enemy as weak as Libya, NATO needs the backbone of US might to fight effectively.

It is not a matter of NATO’s 27 non-US member countries having too few combat aircraft, pilots or bombs. The problem instead is that while some, such as France and Britain, are willing to participate fully, others have limited their roles to noncombat action, and still others have decided not to participate militarily at all.

All have grown accustomed to a far different alignment, one in which the US leads the way and bears the bulk of the combat burden. That is no surprise, given that NATO was created in 1949 as a US-led bulwark against the threat of an invasion of western Europe by the former Soviet Union.

Libya was supposed to have been different.

In his 28 March speech explaining the mission to the American public, Obama described Libya as an instructive example of a problem that does not directly threaten American security. That means that while the United States should help protect civilians there, it should not have to bear the burden on its own, Obama said.

At the time of his speech, NATO had just announced the decision to assume full responsibility for commanding the Libya operation, with the United States providing support such as flying most of the aircraft that provide surveillance and reconnaissance of the battlefield, as well as flying planes to refuel NATO jets.

But how effective has it turned out to be, with a reduced American role?

Gaddafi has not been stopped from pressing the fight against Misrata, the only major city in the western part of Libya that is partially held by rebels; nor have NATO jets succeeded in rolling back those Gaddafi forces that threatened the eastern city of Ajdabiya.

Rebel hopes for a military victory have faded amid pleas for a more aggressive NATO and US air campaign, and even some NATO allies are complaining about a half-hearted effort. Some of the alliance members are sniping at one another, and some are laying blame for the military stalemate at the US doorstep.

The gap between defense spending by the US and its allies is enormous. NATO Secretary General Anders Fogh Rasmussen is fond of saying that whereas 10 years ago the United States accounted for just under half of NATO members’ defence spending, it now is close to 75%.

That explains why, in Libya, the US turns out to have performed more attack missions than it led many to believe it would after the 4 April handoff to NATO control. Pentagon officials on Wednesday disclosed that since the handoff, US electronic warfare planes — with capabilities unmatched by any NATO ally — have dropped bombs on three occasions against Libya surface-to-air missile targets. Those missions have helped keep the skies clear for NATO to fly air patrols designed to keep Gaddafi’s air force grounded.