'Airstrikes alone not enough'

DW: US President Barack Obama is considering carrying out limited airstrikes in the north of Iraq to prevent a humanitarian catastrophe and protect American citizens. Is that the right strategy, in your opinion?

Marco Overhaus: First, it must be said that so far there is no real strategy. Obama has given two very different reasons for authorizing these airstrikes: on the one hand, to protect US citizens and US facilities, and on the other, to prevent a humanitarian catastrophe. These are very different justifications, and that shows that the US government so far has no clear strategy for coping with the challenges in Iraq.

Even if there is no strategy in Iraq, does Obama's announcement at least mark a change of course in his policy on Iraq?

These air strikes would not represent a real turning point or change of course in the US' Iraq policy. They are another step in a gradual process in which the USA is again becoming more and more involved in Iraq's security concerns.

Is the US president even allowed to order such airstrikes of his own accord, that is, without the approval of Congress?

That is a legal grey zone in the USA's constitutional system. Since the Vietnam War, Congress has taken the position that the American president needs Congress's approval to deploy American armed forces or that he must at least obtain this approval after the event. Since then, American presidents have always argued that they don't need to do that. So that is an unresolved legal quarrel in the USA that has not yet been settled and will probably not be settled in the foreseeable future. This quarrel is now also reflected again in the debate on Iraq.

The Americans no longer have any troops stationed in Iraq. Can the fight against the terrorist group "Islamic State" (IS) be won from the air alone?

The USA now has only a very slight footprint in Iraq - in the form of several hundred military observers. Against this background, one has to say that it is very unlikely that air strikes will be enough on their own to halt the advance of IS. Nor will they be able to prevent a humanitarian crisis in northern Iraq.

Let's take a look back in time. Were there comparable operations in recent history where a military success was achieved by means of targeted airstrikes alone?

Airstrikes on their own very seldom or never achieve long-lasting successes as far as stabilizing a particular country goes. This is even more the case when the question of power in a country is undecided and fraught with ethnic rivalries. If you look at history, from Bosnia-Herzegovina, Kosovo and Libya to Iraq, it becomes clear that limited airstrikes in themselves are not sufficient to achieve permanent successes.

Marco Overhaus is a political expert in the "The Americas" research division at the German Institute for International and Security Affairs (SWP). In 2010, he worked as a Transatlantic Fellow at the RAND Corporation in Washington, DC.