The problem is not of Tony Blair’s making. Long before 9/11, he abandoned the conservative “realism” — more accurately, amoral quietism — that had characterised John Major's foreign policies.

Rather than acquiescing in Serb aggression, Mr Blair confronted it. Out of humanitarian obligation and an awareness that failed states breed fanaticism, he sent British troops to preserve Sierra Leone from hand-lopping rebels. Contrary to the Liberal Democrats’ depiction of it as the biggest foreign policy error since Suez, Iraq was the most far-sighted and noble act of British foreign policy since the founding of Nato. Mr Blair’s record exemplifies foreign policy “with an ethical dimension”.

Bien-pensant academics assert that a vote for Blair is a vote for Bush. The reverse is true: President Bush, who as a candidate in 2000 denounced interventionist “nation-building”, has adopted Blairism. After 9/11, Mr Bush’s instinctive conservatism gave way to promoting global democracy as our defence against theocratic barbarism — a strategy that accords with traditional liberal-democratic internationalism.

The party of Michael Foot is now the sole representative of a credible defence policy. The Tories’ tergiversations over Iraq are too cynical even to be dignified with the term “opportunism”; the Liberal Democrats’ predictions about the war (the inevitable refugee crisis; the stymieing of Israeli-Palestinian peace talks) were consistently wrong.

Yet last week The Times revealed that, of new candidates in Labour-held seats, barely one in twelve supported Mr Blair over Iraq. There lies the difficulty for progressive voters. Many Labour candidates, in preferring “stability” to liberty, are closet Kissinger Republicans. Their sole merit is that they are opposed by a Conservative Party whose populism on immigration, student fees and Mr Blair’s character marks a moral and intellectual decline even since the feckless Major Government.

There is a resolution to my dilemma. My Labour candidate (Hove: majority, 3,000) opposes the Government’s revolutionary foreign policies; her challenger, Nicholas Boles, is one of the few Tories to give them principled support. I do not balk at the logic. To support Mr Blair in a Labour marginal, I shall cast my first Tory vote.