Across the Atlantic, conservatives are confused. Prime Minister Blair has announced that Britain’s general election will take place May 5, and conservatives now need to decide whether to vote for their Conservative Party or Mr. Blair’s Labour Party.

Before the presidential election, Mayor Koch, a lifelong Democrat, told me that for the first time in his life he’d be voting Republican. While he disagreed with President Bush on domestic issues, he said that was superseded by the consideration of who would be best to lead the war on terror.

Mr. Koch’s logic was that domestic agenda doesn’t matter at this point in history. If the terrorists manage a deadly strike, there will be no domestic agenda to enact. The one question voters should ask themselves in the voting booth is: Who is best suited to fight the war on terror? For him the answer was the other party’s candidate, Mr. Bush.

British conservatives are reasoning the same – from the other side of the political divide. Domestically, the Tories are a better choice than Labour, at least nominally. Under Labour taxation has increased, the constitution has been dangerously meddled with, and government bureaucracy and waste has multiplied. While the Tories fail to inspire, they’re the safer bet to do the least damage. But that’s irrelevant at the moment.

Even a casual observer of international politics knows Mr. Blair’s position on the war on terror. He’s shown tremendous courage, going against his party, losing friends and ministers, risking his position, to prosecute the war. His reasons are well-known. He believes that the best way to fight terrorism is to expand democracy – “The best defence of our security lies in the spread of our values.”

Even a political pundit, however, will struggle to identify the position of the Conservative Party leader, Michael Howard. He originally supported the war in Iraq. Then, opportunism triumphing over principles, he announced that if knew there were no weapons of mass destruction he wouldn’t have voted for the war. Later he switched to saying he supported the war. Hardly resolute leadership. The war on terror requires a leader who bases policy on security considerations, not polls.

Selecting the leader best suited to prosecute the war on terror in Britain’s case is not just a question of asking who is the most committed. Just as importantly, it’s who is best suited to work with the American president. As John Campbell, Lady Thatcher’s biographer, writes, the Iron Lady understood that America had replaced the United Kingdom as leader of the free world. “Britain’s primary role,” therefore, “was as Washington’s number-one ally.” Americans have to vote for the best leader, the British for the best side-kick.

Mr. Blair beats Mr. Howard easily in this one as well. There is a running spat between the White House and Mr. Howard over his shifting positions on Iraq. According to the British press, Karl Rove banned Mr. Howard from visiting the White House – and indeed he hasn’t been since. In return Mr. Howard snubbed the summer’s Republican convention in New York.

The friendship between the prime minister and president, meanwhile, is well-known. What Thatcher was to Reagan, Blair is to Bush. The prime minister said: “We in Britain stand with you … Your problems will be our problems, and when you look for friends we will be there.” The president responded: “In a dangerous world one element that goes without question: Britain and America stand side by side.” That’s actually a Thatcher-Reagan exchange, but could have been a Blair-Bush one.

In private, Conservative politicians insist Mr. Howard was “just playing politics,” over Iraq and WMD. If elected, however, he would be just as pro-American, and pro-war on terror as Mr. Blair, they say. That may well be the case, but most would prefer to trust a man who says what he believes both publicly and privately. Nor do people have much respect for someone who plays politics with national security.

Mr. Freedman writes from London.