John Howard's attack on US presidential candidate Senator Barack Obama was ill-conceived and ill-considered. It was bad politics and bad foreign policy. Few arguments are won by resorting to personal abuse. Evidence, not emotion, is required for the Prime Minister to win his argument.

Opposition Leader Kevin Rudd was accurate when he said that the implication of the Prime Minister's remarks was that the Democratic Party of the US was effectively the preferred party of terrorists.

Good people with good intentions can, and do, differ over Iraq. At a personal level a number of Liberal MPs would prefer the early withdrawal of Australian troops from the region.

But a vote for those MPs at the next federal election is hardly a vote for terrorism. It is precisely because the Iraq war is so controversial that the Prime Minister must handle those who differ from him with sensitivity. Howard is right when he says that withdrawal of allied forces from Iraq by March 2008 as advocated by Senator Obama would be a victory for al-Qaeda. But by itself this analysis proves nothing. It provides no guide as to how long the US should continue to occupy Iraq, nor what the measures of success in the war should be. To maintain support for US and Australian troops in Iraq, George Bush and John Howard can no longer rely on the argument that "we can't afford to lose".

Some in the West would sacrifice the freedom of the Iraqi people for the sake of seeing the US beaten. But this is a tiny minority. The debate about radical Islamic terrorism is not whether to stop it - it is about how to stop it. It is a debate about means, not ends.

The war on terror could continue for a generation. Over that time there will inevitably be disagreement over strategy, and even the definition of victory. But simply because two sides disagree shouldn't be taken to mean that one side is "softer" on terrorism than the other.

The PM's dramatic lapse of judgement is out of character. Although his critics won't admit it, he usually handles foreign policy and security issues with confidence and success. For example, he still has not received the credit he deserves for securing the independence for East Timor, and then rebuilding our fractured relationship with Indonesia.

But all of this is in the past. It is the future that counts.

The harm that John Howard has done is not to the Australia-US alliance. The relationship is robust enough to withstand these sorts of tensions, regardless of whether Senator Obama, or Hillary Clinton, or another Democrat is elected to the White House. It's unlikely that the US House of Representatives and Senate "may yet make Australia pay for this blunder" as claimed yesterday by Robert McClelland, Labor's shadow minister for foreign affairs. What's in the perceived best interests of America at the relevant time will determine how a Democrat-controlled government treats Australia. Actual or perceived personal insults won't determine US international policy.

Domestically, the political injury Howard has caused probably won't be significant in the long-term. The ALP will continue their attack on the issue against the Coalition, and will attempt to prove that Howard's personal relationship with Bush has affected his capacity to determine what's in the national interest. Labor is unlikely to sway anyone who does not already have an opinion about the worth or otherwise of Australia's special connection to the US.

The real and potentially long-lasting damage caused by the Prime Minister is to the very cause he is fighting for. John Howard wasn't wrong when he claimed that "If America is defeated in Iraq, the consequences for the West will be catastrophic". The danger is that the truth of this message has been lost. Those who support democracy in the Middle East don't advance their argument by insinuating that somehow the US Democratic Party is less hostile to terrorism than George Bush.

Advocates of an early withdrawal, such as Senator Obama and the ALP, have no response to the question of "what happens next" if and when allied forces leave Iraq. Whether Obama and the ALP would abandon the country to a civil war in which potentially hundreds of thousands would die is something they have left unanswered.

Withdrawal from Iraq within the next 12 months would very significantly reduce the willingness of America to involve itself on humanitarian grounds in future conflicts anywhere else. It's a paradox that many of the people arguing for a retreat from Iraq at the same time demand that the US act to stop the killing in Sudan.

These are the real issues to which Senator Obama and the ALP must respond. The Prime Minister's comments this week are a very unfortunate diversion from the challenges ahead.

John Roskam is executive director of the IPA.  Article originally published in today's Age, reprinted with generous permission.