DW: President Donald Trump launched the missile attack against a Syrian air base exactly 100 hundred years after the United States entered World War I. Do you consider this as merely a coincidence or do you see some historic significance in this?

Andrew Bacevich: I am sure it is totally coincidental. I seriously doubt that President Trump realizes that the US entered World War I 100 years ago. He is not particularly literate when it comes to history.

It is difficult for us outsiders to know exactly what is shaping the president's behavior. If we take his words at face value, he has suddenly discovered his inner humanitarian self. And as a consequence of that, a president who had been quite clear that the US had only minimal interest in events in Syria has now discovered that we have a vital interest, an interest that is so important that we have now launched hostilities against Syria. This attack is little more than a pinprick. It is one of those send-a-message military gestures.

It is possible, I suppose, that Assad will correctly interpret that message and suddenly learn to behave. I think it is more likely that he will reject the message and that this event will actually mark the beginning of what is likely to be a more protracted and probably more violent US military involvement in the events that are unfolding in Syria. With what consequences, with what results, is impossible for us to say at this time.

Brian Linn: As a historian, I don't think the two events are connected. And I just have the same information available about this as everyone else does. But this is a president who likes to have a reactive style of leadership in contrast to President Obama, who liked to be very methodical and plan events and try to anticipate consequences. President Trump prefers a different, we might call it a more tactical style, of leadership in which he reacts to immediate circumstances - and unpredictably.

Some observers worry that this kind of a military intervention without an apparent clear strategy or an outlined endgame could become a slippery slope that draws the US fully into the Syrian civil war. From a historical perspective, is this fear merited?

Andrew Bacevich: It is absolutely merited. The relevant history here is not necessarily the history of World War I; it is the history of earlier US efforts to achieve regime change in this region. And I introduce that term because Secretary of State [Rex] Tillerson has said that it is now US policy that President [Bashar al-Assad] departs. So that would seem to suggest that we are back in the regime change business in Syria. The relevant lessons are, I think, what regime change produced in Iraq and in Libya, where getting rid of the evil dictator turned out to be the easy part. The far more difficult part was to try to create then some sort of new order that would follow the dictator's departure. And those efforts in both Iraq and Libya have been catastrophic and expensive. So what it is that leads this administration to think that we are going to do a better job in Syria very much remains to be seen.

The president's decision to launch what is likely to become a war in Syria occurred over a period of about 48 hours. It appears that there was minimal consultation with anybody outside his inner circle, and it needs to be seen whether this compact approach to decision-making is going to produce a more enlightened approach to what to do next than was the case when George W. Bush invaded Iraq and when Barack Obama was involved in overthrowing Moammar Gadhafi.

Brian Linn: It is interesting a German would suggest that since you produced Clausewitz, who said that war was unpredictable by nature. In the 19th century many of these interventions were also reactive, and they were also conducted in the very short term, for instance sending the Marines ashore to strike back at pirates or firing at ports in Korea that were seen as provocative. So there is a tradition of these interventions that goes back almost 200 years and most of them were very short-term - punitive expeditions or showing the flag or what we used to call gunboat diplomacy to intimidate people - and then they disappeared and there were no long-term consequences.

There have been other interventions, usually the larger interventions such as in the Philippines, that grew far beyond the original intent. So a good historian can find examples on both cases. In the short term, something like this that is a punitive strike tends to have no long-term consequences, if you go by the historical record. 

What is your assessment of President Trump as commander-in-chief compared to his predecessors so far?

Andrew Bacevich: Everything that we have seen of Trump both as a presidential candidate and in his first weeks of his presidency suggest that he is a person of uneven temperament, that he is impulsive, that he asks and speaks without thoroughly thinking through the consequences of what he says and what he does, and I think that this initiative is consistent with that earlier bit of behavior.

The sudden reversal in the way the administration defines the problem in Syria from my point of view has to be causing great puzzlement in other capitals of the world. What should leaders in Beijing, in Moscow, in Pyongyang and in Tehran make of this? But it's not just adversaries; it's allies as well. What are the leaders in Seoul, in Tokyo, London and Berlin to make of this? There is a great virtue in statecraft, to consistency, to predictability. But that is simply not the style of this American president.

Brian Linn: That is very hard to tell since he has been in office only for a very short time. We can't really tell at this time. I think any historian that would make a decision at this time would be speaking more from their political convictions than from a sense of history. We look at long-term consequences and can't base this on what "The New York Times" says. That is for political scientists and international relations specialists and journalists to do.

Andrew Bacevich is professor emeritus of international relations and history at Boston University and a graduate of the US Military Academy at West Point.

Brian Linn is professor of history and liberal arts at Texas A&M University and the former president of the Society for Military History.

The interviews were conducted by Michael Knigge.