The first reaction was relief. The UN security council resolution 1973 authorising foreign intervention in Libya was held up as an attempt to protect the Libyan rebels and alleviate their suffering, and who would not welcome that? Who would not want to stop a bully intent on "wiping out" those who oppose him? But any relief should be tempered by serious misgivings.

First, what motives lie behind this intervention? While the UN was voting to impose a no-fly zone in Libya, at least 40 civilians were killed in a US drone attack in Waziristan in Pakistan. And as I write, al-Jazeera is broadcasting scenes of carnage from Sanaa, Yemen, where at least 40 protesters have been shot dead. But there will be no UN no-fly zone to protect Pakistani civilians from US attacks, or to protect Yemenis. One cannot help but question the selective involvement of the west in the so-called "Arab spring" series of uprisings.

It is true that the US was reluctant to act and did so only after weeks of indecision. Unwilling to become embroiled in another conflict in the region where it would be perceived as interfering in the affairs of a sovereign state, Obama wisely insisted on a high level of Arab and Muslim involvement. At first the signs were good: the Arab League endorsed the move last week, and five member states seemed likely to participate. But that has been whittled down to just Qatar and the UAE, with Jordan a possible third. This intervention lacks sufficient Arab support to give it legitimacy in the region.

The US was worried about the cost of military action, too, given its ailing economy. Abdel Rahman Halqem, the Libyan ambassador to the UN, has told me that Qatar and the UAE have agreed to foot most of the bill for the operation. And what is the motive of these autocratic states: to protect the Libyan people, a grudge against Gaddafi, or to bind the US further into the region?

So this is the second problem: the main players in this intervention are western powers led by Britain and France with US involvement likely. If Libya's neighbours, Egypt and Tunisia, were playing the leading role that would be something to celebrate. Democratic countries helping their neighbours would have been in the spirit of the Arab uprisings, and would have strengthened the sense that Arabs can take control of their future. It could have happened too: Egypt gets $1.3bn of US military aid a year. Diplomatic pressure by Hillary Clinton could have brought that mighty war horse into the arena, or at least encouraged Egypt to arm the rebels. Instead, an Egyptian foreign ministry spokesperson stated categorically on Wednesday: "No intervention, period."

The third problem is that, although he is often dismissed as mad, Gaddafi is a master strategist and this intervention plays into his hands. He quickly announced a ceasefire in response, which was claimed by some as an early victory for the UN resolution; in fact, it both deflates the UN initiative and allows Gaddafi to appear reasonable. Meanwhile, a ceasefire at this point suits Gaddafi: under its cover, the secret police can get to work. Similarly, Gaddafi accepted the earlier arms embargo: again, this apparent concession suited him. His regime has sophisticated weaponry, whereas the rebels have few arms.

Gaddafi knows how to play the Arab street, too. At the moment he has little, if any, public support; his influence is limited to his family and tribe. But he may use this intervention to present himself as the victim of post-colonialist interference in pursuit of oil. He is likely to pose the question that is echoing around the Arab world – why wasn't there a no-fly zone over Gaza when the Israelis were bombarding it in 2008/9?

Unlike in Tunisia and Egypt, the uprising in Libya quickly deteriorated into armed conflict. Gaddafi could question whether those the UN is seeking to protect are still "civilians" when engaged in battle, and suggest instead that the west is taking sides in a civil war (where the political agenda of the rebels is unknown).

And what of the long-term impact of this intervention on Libya, and the world? Here lies yet another concern. Libya may end up divided into the rebel-held east and a regime stronghold in the rest of the country which would include the oil fields and the oil terminal town al-Brega. There is a strong risk, too, that it will become the region's fourth failed state, joining Iraq, Afghanistan and Yemen. And that ushers in another peril. Al-Qaida thrives in such chaos; it played a key role in the Iraqi and Afghan insurgencies and is based in Yemen – and it may enter Libya, too. Several of Bin Laden's closest associates are Libyan, and Gaddafi is no stranger to terror groups – the Abu Nidal Organisation found a safe haven in Libya from 1987 to 1999. Gaddafi has also threatened to attack passenger aircraft and shipping in the Mediterranean.

Fifth, there is no guarantee that military intervention will result in Gaddafi's demise. In 1992, the UN imposed two no-fly zones in Iraq – to protect the Kurds in the north and the Shi'a in the south. Saddam remained in power for another 11 years and was only toppled after an invasion. To date, over a million civilians have died in Iraq. The international community has a duty to ensure that this sorry history is not repeated in Libya.

Finally, there is the worry that the Arab spring will be derailed by events in Libya. If uprising plus violent suppression equals western intervention, the long-suffering Arab subjects of the region's remaining autocrats might be coerced into sticking with the status quo.

The Libyan people face a long period of violent upheaval whatever happens. But it is only through their own steadfastness and struggle that they will finally win the peaceful and democratic state they long for.