Leading Article: . . . and one that might help him

THE conditions seem to be in place for an air assault on Iraq. The Americans have their aircraft ready; there has been a flurry of stories in which anonymous Washington sources have claimed that an air strike is imminent, and would be welcomed by all Iraq's neighbours. The team of United Nations observers searching for evidence of Saddam Hussein's nuclear and biological arsenal is due to be withdrawn tomorrow morning.

The New York Times yesterday asserted that an incident would be manufactured this week to allow airstrikes to be made. This has been roundly denied, but the denials are as otiose as any manufactured incident would be. President Saddam continues to combine atrocity with insolence, most recently in the use of napalm against the rebels in the south. He has repeatedly broken the letter as well as the spirit of the ceasefire agreement. The teams of observers sent to monitor his compliance with the ceasefire agreement have been constantly harassed and humiliated. The Iraqi media have repeated the irredentist claim to Kuwait which started the last war. There have been reports, most recently from Tehran but also from UN sources, that President Saddam has used fixed-wing aircraft as well as helicopters against the Shia and Marsh Arab rebels in the south of the country.

To some extent this brinkmanship is in the interests of both President Saddam and President George Bush. Each stands to win a great deal if he can humiliate his adversary publicly. The risks of misjudgement are correspondingly large. 'He still has a job', say the Democratic bumper stickers in the US, over a picture of President Saddam. But curbing him serves much larger interests than those of the Republican Party in an election year. He remains as evil and ruthless as he was portrayed in the run-up to the Gulf war. It is obviously in the interests of the long-suffering inhabitants of Iraq that President Saddam be toppled. It is also a test case for the authority of the United Nations.

Since his defeat in the Gulf war, President Saddam has shown the skills and judgement of a really considerable bully: drawing back from any act that would force the Americans into further action, while capitalising on every weakening of the line taken against him by the wartime allies.

There is one glaring exception to this tactic: his use of fixed-wing aircraft against internal rebels. Such missions were clearly prohibited under the ceasefire agreement. Unlike the existence of documentation, which may be hidden somewhere in the ministries the UN keeps trying to search, the missions flown by his fighter-bombers can be proved. Even if this proof is not made public, it is inconceivable that the Americans do not know that the Iraqi airforce is flying missions against rebels in the south. Certainly, the rest of the world believes it is.

The US should announce, and mean, that any Iraqi military aircraft which takes off without authorisation will be shot down. Kurdistan is already under the protection of an allied air umbrella; there is no great difficulty of principle in extending that protection to the rebels in the south. Such an operation may not have the glamour of bombing ministries in Baghdad. It would be a simple, and long-overdue deployment of military force for humanitarian ends.