It will be harder to dislodge the IRA from Belfast than the Syrians from Lebanon

Gerry Adams has gone through worse than this before, and he thinks that he has the measure of Tony Blair

Suddenly, optimism seems to be triumphing over intransigence. In both Beirut and Belfast, popular protests have thrown oppressive regimes on the defensive. Bashir Assad is struggling to retain control of Lebanon; Gerry Adams, of the Catholic areas of Belfast. Both men have had to make concessions to their critics, who remain unappeased and are keeping up the attack.

Suddenly, optimism seems to be triumphing over intransigence. In both Beirut and Belfast, popular protests have thrown oppressive regimes on the defensive. Bashir Assad is struggling to retain control of Lebanon; Gerry Adams, of the Catholic areas of Belfast. Both men have had to make concessions to their critics, who remain unappeased and are keeping up the attack.

This is all heart-warming. But it would be foolish to assume that everything had been transformed, in either city. In both, caution is necessary. The resources of malice are not exhausted.

It will be easier to end Syrian rule in Lebanon than to eliminate the IRA. Indeed, we are now in the last phase of the Syrian occupation. This does not mean, however, that peace and security are guaranteed. There is a quotation which I overuse because it is so often applicable. The words are Yeats's and they apply to Lebanon as to Ireland: "Great hatred: little room".

Even smaller than Ireland, Lebanon is even more racked by ethnic and religious divisions. The hope now is that decades of civil war and Syrian oppression have created a new realism and that enough Lebanese want to live in peace, not drown in blood. But that remains a hope, not a certainty.

Belfast would appear to be easier. Most commentators have assumed that the combination of a record-breaking bank robbery and a brutal murder has left the IRA/Sinn Fein discredited and that the Shinners will only be able to recover their position if the IRA does finally discharge its obligations under the Good Friday Agreement. If only that were so.

It is true that in the Republic, the IRA/Sinn Fein has come under pressure. The Irish Minister of Justice - and deputy Prime Minister - Michael McDowell has scornfully ripped apart the pretence that there are two organisations. He has tied Sinn Fein's politicians to crime and blood. This has had some effect on the opinion polls.

In the South, Sinn Fein has two important electorate assets. The first is the romantic appeal of physical force republicanism; there are endless ballads which sentimentalise homicide. The second is the Gerry Adams brand image. Because of recent events, both have suffered. Physical force republicanism is supposed to be about acts of daring in combat with the British army, not kicking a man to death outside a pub - nor even robbing banks. As a result of all that, and of his own evasiveness, Adams's poll standing has fallen by 20 per cent in the south.

If only that were conclusive; if only its continuance could be guaranteed. In that regard, there is one immediate problem: the British general election. One might have hoped that Sinn Fein would now be under threat in its current four seats. On the contrary, alas. It seems almost certain that they will be held and that the Shinners will wade through Robert McCartney's blood to at least one gain. The SDLP, the constitutional national party, seems incapable of shaking itself and arresting its decline. As long as it remains so ineffective, Sinn Fein's electoral position in the North is under no threat. Its leaders will hope that things will have moved on before the next important elections in the South.

That is all too likely, and not in a favourable direction. The Shinners are used to bouts of unpopularity and are already working out how to counteract this one. In the North, it will soon be the marching season, and Sinn Fein is planning a long, tense summer. It will take every opportunity to confront the Orangemen and to make the Catholic community feel that it is under siege. The Shinners will try to use the Orangemen's bowler hats to efface the memories of bank raids and blood stains.

Sinn Fein also believes that it can play on Tony Blair's desire for a deal, at almost any price. In 2002, in a speech in Belfast, the Prime Minister said that if Sinn Fein were to be allowed back into government in Belfast, it would have to pass the same tests as applied in Dublin. The IRA would have to disarm and disband.

By last December, however, everything had been softened. Mr Blair was desperate to negotiate the Ulster version of the Hitler-Stalin pact; a deal between Sinn Fein and Ian Paisley's Democratic Unionist party, which would allow a devolved government to be formed in Belfast. If Ian Paisley had been given a few photographs of IRA weapons being destroyed, there would have been a deal, with no barrier to the IRA's criminal activities in the areas it controls. If it had not been for the bank raid, Tony Blair would already have renewed his efforts to broker a devolved settlement, on a basis that would enable the IRA to retain its military structures.

The IRA leadership believe that they have an insight into Mr Blair's thinking. They are sure that he is so terrified about the political consequences of a resumption of bombing in Britain that he will never put them under too much pressure. This always gives them the option of delay. If they do not like the terms of a proposed deal, they can merely reject them on the assumption that after a short interval the British will work on the Unionists to make more concessions.

Assuming that Mr Blair is re-elected, the IRA/Sinn Fein expect that process to begin all over again. There is also talk in Shinner circles of a cunning ploy which might help to win over Mr Blair. Instead of the awkward two Ds, disarmament and disbandment, what about a third - divorce? Might it be possible for Sinn Fein and the IRA to announce that they have split up and are now two separate bodies?

It would require a high order of cynicism to make such a proposal; a higher one of naivety to accept it. But the IRA believes that Tony Blair is desperate to believe them.

Yet a rescue may be at hand. There are suggestions that Mr McDowell regards the December deal as far too generous towards the Shinners, and that this is why he has been so determined to link them to the IRA.

In the South, an increasing proportion of the political elite is now post-republican, post-Gaelic, even post-Catholic, in its thinking. To it, the Celtic heritage is something for the tourists. It is far more interested in the further successes of the Celtic tiger: high-tech, European-minded and internationally competitive. It sees the IRA/Sinn Fein as a threat to all that, because it could undermine political stability in the South.

There is an irony. For years, British officials would complain that Dublin was far too ready to make excuses for the Shinners while refusing to recognise the merits of the Unionist position. It may now be that the roles have reversed, and that it will be Dublin which opposes London's attempts to give the Shinners too much legitimacy on too easy terms.

So it would be premature to assume that it will be as easy to dislodge the IRA from its ghettos as the Syrian troops from the Bekaa Valley. Gerry Adams has gone through worse than this before, and he thinks that he has the measure of Tony Blair. We can only hope that Mr Blair, or an alternative prime minister, will prove him wrong.