LAST SPRING, demand for political reform coalesced in a part of the world so far resistant to constitutional democracy. Nine million Iraqis voted in the country’s first post-Saddam election. Protests in Lebanon led to the withdrawal of Syrian troops. Plans were made for municipal elections in Saudi Arabia (though with an all-male franchise) and presidential elections in Egypt. Syria’s dictatorship was increasingly isolated. It was not yet an Arab spring, but it may yet mark — in the phrase of one Middle East scholar — the autumn of the autocrats.

These developments validate the strategy of “regime change” pursued since 9/11. Critics dispute this, but they are on weak ground. Altering the balance of power in the Middle East was the declared aim of the Blair-Bush approach. If it is premature to say the plan is working, then at least the plan is consequential — in stimulating political reform, in Libya’s abandonment of weapons of mass destruction, and in rolling up the A.Q. Khan nuclear network in Pakistan.

The case for regime change is the link between Western security and political institutions. In the months preceding the Iraq war it was thought politic to emphasise what turned out to be bad intelligence on Saddam’s arsenal. There was always a more fundamental consideration. This was the notion of removing the conditions that breed terrorism.

The “root causes” of terrorism became a cliché after 9/11. Whenever these were stated, they turned out to be whatever the critic had been campaigning about on and before 9/10 — Third World poverty and a Palestinian state, among other candidates. Yet recent academic research suggests that the cause of terrorism is not poverty — if it were, then sub-Saharan Africa would be the obvious source of anti-Western terror — but political repression. Societies where dissent is confined to religious absolutism are incubators of anti-Western fanaticism. The case for regime change ought to have been stated in a way at least as succinct as the claims of Saddam’s WMDs and with greater plausibility. Without intervention to remove the worst of governments and assist Iraqis to build a constitutional democracy, the pathologies tolerated by autocratic regimes would flourish. Anti-totalitarianism is our own defence.

Whether Iraq will become a stable democracy is unclear, and those trying to make it so have been failed by the Bush Administration’s incompetence. But, at a minimum, Iraq can be a state where essentials of order and constitutionalism are observed. The Left has an important argument on what those requirements comprise. A liberal state is not necessarily a lightly governed state. Building a consensual democracy will be easier if social policies are not left to unregulated markets and minimal welfare provision.

Regime change has been a political liability for Tony Blair, but he has been right. His strength is that he has a synoptic view of the struggle against terror. Critics of interventionism see the attack on the twin towers as a discrete event to be countered by better law-enforcement, police work and diplomatic pressure, with force as a remote contingency. But a juridical approach to fighting terror founders on the brute fact that international law lacks a sovereign body capable of implementing it, other than the states that subscribe to it. Swayed by the sheer unlikelihood of a totalitarian movement dedicated to the political realisation of apocalypse, critics of interventionism lack a sense of the gravity of the threat. Peace campaigners too lack a sense of the ridiculous. Bruce Kent, of CND, declared after 9/11: “I think we need to pursue bin Laden in different ways . . . I would even go as far as combing through bank accounts across the world and freezing anything suspicious.” These are dark times indeed if Mr Kent would even open a bank statement not addressed to him.

Mr Blair perceives that George Bush is a man of common goals. Despite his realist rhetoric in the 2000 presidential campaign, Mr Bush has little conservative scepticism about exporting democracy. This is an important shift in US foreign policy. The enduring weakness of America’s stance in the Cold War was its willingness to ally with authoritarian governments to resist communist totalitarianism. Bush’s innovation is to recognise the limits of realism.

In the realist model, states are often compared to billiard balls: a ball’s internal composition is opaque and unimportant; what matters is how the ball interacts with others on the table. The model’s weakness is its failure to address the power of ideas. By contrast, Bush believes the spread of liberty, not the search for allies in an eternally shifting balance of power, is the guarantor of Western security. His reasoning explains the interventions in Afghanistan and Iraq, but also his distinctive stance on the Arab-Israeli conflict: pressing for internal reform in the Palestinian Authority while being the first US President to aim explicitly for a Palestinian state.

The Blair-Bush strategy ought to be a bipartisan cause. In recent history (notably Bosnia and Kosovo) the Conservatives have argued for strict constraints on the exercise of national power. Simultaneously much of the Left (including the Liberal Democrats) has been infected with a reactionary preference for stability rather than liberty in the international order. The anti-totalitarian Left has a responsibility to help to forge a new coalition for the spread of liberty, recognising that its historic ideals are now expressed in the unlikely trappings of US strategic doctrine.

The author’s Anti-Totalitarianism: the Left-Wing Case for a Neoconservative Foreign Policy (Social Affairs Unit, £13.99) is published on Friday.

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