Rupert Cornwell: Americans are confused about this – none more so than their President

Arm the rebels? Foment a palace coup or a tribal revolt to overthrow Gaddafi? Step up the bombing? Or settle for a stalemate that seals a de facto partition of the country? For the Nato-led coalition seeking to remove the Libyan leader from power, there are no easy answers – and certainly none that guarantee success.

In the last 24 hours, talk has grown in Washington and other Western capitals of supplying arms to the ragtag army that once again is being driven back by a rocket and artillery bombardment from Gaddafi's vastly better equipped forces. And this despite the no-fly zone and Nato air attacks on the regime's weapons depots and other targets.

"I'm not ruling it in, and I'm not ruling it out," President Barack Obama said of sending arms, in a network TV interview on Tuesday evening that implicitly confirmed the divisions within the administration on the issue. Hillary Clinton, the Secretary of State, insists the US has the right to do so under UN Resolution 1973, which authorises all necessary means to protect civilians – and she and the Defence Secretary, Robert Gates, delivered that message yesterday in a closed-door briefing for Congress on the Libyan crisis.

The session was designed to build on Mr Obama's national address this week and the London conference on Libya, to show that the administration has a coherent strategy that will not lead to US boots on the ground, in another Muslim country in another open-ended war. The address appears to have achieved that goal, at least in part. Democrats were strongly supportive, though some Republican hawks, including Mr Obama's 2008 opponent John McCain, said the President should have made Gaddafi's ousting the explicit aim of the campaign.

But the country is unconvinced – and an opinion poll yesterday put Mr Obama's job approval rating at just 42 per cent, perhaps reflecting dissatisfaction at his handling of the situation in Libya. A separate poll found that fewer Americans regard him as a strong leader, a sign, maybe, of the public's confusion over the US mission.

Arming the rebels may seem a neat solution to the dilemma of how to beef up military resistance to the Gaddafi forces without committing US ground troops. But, as experts quickly pointed here, the potential pitfalls are many.

In the first place, it may not work – at least not as fast as Western governments would like. The disorganised Libyan opposition fighters must be trained to use the weapons. That, precedent suggests, could be the first step on a slippery slope. Foreign trainers can soon become foreign "advisers", and US advisers have a way of turning into US troops, as happened in Vietnam.

Second, the policy could backfire. In the 1980s, America armed the Afghan mujahedin, helping them drive the Soviet Union out of Afghanistan. But that resistance turned into the Taliban, and Afghanistan became the sanctuary of al-Q'aida and Osama bin-Laden.

And if the rebels do ultimately succeed, such problems could arise again. US officials freely admit they cannot be sure who they are dealing with, and what sort of government would emerge in a post-Gaddafi Libya.

In short, there are no easy answers. Nato says it will keep up its intervention until the Libyan leader is gone. But that could take a while, with no guarantee the public will stay patient. The US and its allies may hope a palace coup or a tribal uprising will do the trick sooner. But that is merely a hope.

The options - and the possible outcomes

Arm the rebels

Positives

Despite allied air strikes, the rebels complain the pro-Gaddafi forces have superior weapons. Arming them against the regime would make their fight easier and, crucially for Western politicians, quicker.

Negatives

The US armed the Afghans in 1979, only for the weapons to be used against them after 2001. There are concerns about an Islamist element in the anti-Gaddafi forces. With discipline poor, weapons may not be the true problem.

And who wants it

Few main coalition members want publicly to back the move, but David Cameron refused to rule it out yesterday. Hillary Clinton has also hinted that the US may agree. There could be legal difficulties, especially with an arms embargo in place.

Kill Gaddafi

Positives

This would remove the regime's figurehead. After more than 40 years in power, he has removed all rival power bases; if he were killed, the opposition would hope that the regime would not survive the vacuum.

Negatives

The UN resolution supporting military action does not allow assassination per se, but officials say the situation is ambiguous if it can be proved Gaddafi is running the Libyan military.

And who wants it

Liam Fox and William Hague hinted that such a move is possible. General Sir David Richards, the British chief of the defence staff, said that killing Gaddafi was 'absolutely' not an option. Opinion differs similarly in the US.

Do nothing more

Positives

Not acting beyond enforcing the no-fly zone would, once Gaddafi's forces are sufficiently disabled, allow Nato to operate with a skeleton staff in Libya. There would be little risk to Nato pilots while civilians in eastern Libya would be protected.

Negatives

As Iraq showed, merely enforcing a no-fly zone would not prevent Gaddafi's secret services from carrying out reprisals against the opposition. It would also be a loss of face for Western leaders who called on Gaddafi to go.

And who wants it

All of those signed up to the UN resolution have an interest in maintaining the no-fly zone, but few want to be trapped in a protracted conflict. Few, other than Gaddafi, have said they expect the war to last longer than a couple of months.

Ground troops

Positives

The strong argument in favour of deploying ground troops is to overcome Gaddafi's forces in the shortest possible time. Nato-backed ground troops could be in Tripoli in days.

Negatives

Policymakers are unlikely to want to get into a long conflict, risking Western troops, so soon after Iraq. "Boots on the ground", even peacekeepers, is likely to be unpopular.

And who wants it

Very few nations. Some people in Benghazi called for any action to prevent Gaddafi from reaching the city, but now that regime forces have been beaten back, any residual support for that has vanished.

Send Gaddafi into exile

Positives

Forcing the Libyan leader in to exile, Western governments hope, would have almost the same impact as killing him. There have been numerous calls for him to go voluntarily, to no avail, but certain leaders still see exile as the best option.

Negatives

If Gaddafi is allowed to go now, he would avoid a trial for war crimes – a key demand of many rebels. There is also the question of where he could go, having upset most of his neighbours – Venezuela appears to be one of his best options.

And who wants it

It's rumoured that Gaddafi considered leaving, but unlikely if his troops are still making progress. Italy, a key trading partner, has pushed the idea of his moving to an African country not signed up to the International Criminal Court.