After only a month in office, President Barack Obama has bumped up against the realities of war-and-peace decisions that face any American president.

The president’s order not to withdraw from Afghanistan but to get further into it shows that there are limits to the liberalism he has espoused, even though he foreshadowed this move during his election campaign. He is not the first US president to come into office promising change and then finding that more of the same is part of the policy mix.

The Carter experience

Jimmy Carter proclaimed an "ethical” foreign policy but then ran into the reality of the Soviet move into Afghanistan in 1979. This led to a freezing of relations with Moscow, including a boycott of the Moscow Olympic Games.

Worse was to follow for Mr Carter as American hostages continued to be held for over a year by Iranian revolutionaries at the US embassy in Tehran.

President Carter tried to get their release through ineffective sanctions and then a rescue operation that came to grief in the desert outside Tehran.

It was an event that doomed his presidency, though he would probably have lost to Ronald Reagan anyway, because the US was then, as now, in an economic recession and, at that time, thoroughly demoralised.

Jimmy Carter chose not to go to war with Iran, something that George W Bush might have at least threatened. A huge decision about war or peace potentially looming over the horizon for President Obama also concerns Iran.

It is curious how the same places crop up again and again in differing circumstances and never with an easy answer. That potential crisis is of course over Iran’s nuclear activities.

Defying the International Atomic Energy Agency and the UN Security Council, which want it to halt the enrichment of uranium, Iran is continuing to enrich, though it says it has no intention of using this expertise to build a nuclear device.

Mr Obama has promised new contacts with Iran and everyone is waiting to see if this will include an offer to agree to some enrichment at least by Iran - or whether this confrontation becomes a crisis and even a war.

Iran might prove to be the crucial test of what kind of President Obama will be internationally.

Mr Obama has not developed the concept of an ethical foreign policy as Jimmy Carter did. He has not made that kind of commitment. But even presidents who want to avoid war sometimes find that war is, in their opinion, thrust upon them.

Bill Clinton managed to find his own solution, by limiting the kinds of wars he fought, turning them into campaigns instead. He bombed but did not invade Iraq; he bombed and did not invade Serbia, resisting the pressure of UK Prime Minister Tony Blair for ground operations as well.

Truman and Korea

US President Harry Truman did go to war in 1950, when he opposed the invasion of South Korea by the North. The Korean War was unpopular and Truman left office with his head high and his polls low. But history has revived his reputation.

If President Obama can avoid an attack on Iran yet resolve the argument with Iran, his reputation could be made in a different way. But the danger for a liberal president is that he is seen to be weak if he does not take action.

Guantanamo prisoners

Another problem down the line will raise acute dilemmas for a liberal-minded lawyer president. It concerns those prisoners held at Guantanamo Bay who might not face trial but who will not be released.

When the camp closes, which the president has ordered inside a year, there could be a small number of these prisoners. The question then will be whether to hold them in some form of preventive detention on US soil, perhaps after a ruling by a new national security court, which would give a legal veneer to detention without proper trial.

It would not be pretty in the eyes of the powerful element of legal, public and political opinion that has forced the promise of Guantanamo’s closure. And for a president with his legal background, it would not be easy to justify on constitutional grounds.

It might well go all the way up to the Supreme Court - but it might be a decision that a liberal president would feel he had to take.

BBC