Obama could have directly initiated a military strike against Syria, but the US president opted instead to seek congressional approval first. The move reflects parliaments getting increasing say on military intervention.
For Germany, it's par for the course: when the federal government wants to pursue direct military intervention in other countries, it requires parliament's green light. The country's highest court, the Federal Constitutional Court, made that clear in a 1994 decision.
However, the parliamentary stepping stone has spelled headaches for the government on more than one occasion.
In 2001, former Chancellor and Social Democrat Gerhard Schröder was set to send German armed forces to Afghanistan. But opposition emerged from within his own governing coalition with the Green Party. In order to achieve a unified front, Schröder coupled his request for parliament to authorize a military strike with a vote of confidence on his government. Few members of his coalition were willing to risk voting against the war but simultaneously voting their government out of power.
"In German history, we've had bad experiences with letting the power for decisions rest too firmly in the hands of one person or a few individuals," said Christian Mölling, an expert on security policy at the German Institute for International and Security Affairs (SWP), with regard to Germany's legal framework that provides checks on the power to go to war.
The country is hardly alone in its approach. Among NATO member states, the governments of Denmark, Lithuania and Turkey must each seek a parliamentary go-ahead before going to war. EU members Austria, Ireland and Sweden have similar requirements.
Looking for cover
As commander-in-chief of the armed forces, the US president is not subject to a similar approval procedure. Obama could have initiated strikes in Syria as soon as he decided that was the best course of action - under two conditions. He would have had to inform Congress of the move within 48 hours, and the strikes would have faced a time limit of up to 60 days. After that point, Congress would have to approve continued military action.
The situation in Britain is similar, where Prime Minister David Cameron could have immediately authorized retaliation for an alleged chemical attack by the Syrian government. In Britain, the Queen is officially the commander-in-chief of the armed forces, but this role has been taken over by the prime minister in practice. Parliament does not have to approve military action.
However, the prime minister can seek a non-binding vote from parliament, as Cameron did, when it comes to matters of war. The prime minister had hoped that parliament would support his plans to send a warning to the Assad regime. But the motion failed, and Cameron's hands are now tied so long as he respects the representatives' decision.
A wide majority in France now also believes parliament should have a say in whether the country gets involved militarily in Syria. In a poll by broadcaster BFMTV, 74 percent said there should be a vote.
As in the US and the UK, France does not legally mandate parliamentary approval for military action. The country's constitution says the head of state decides on strikes by the armed forces. But France's minister for relations with parliament, Alain Vidalies, stressed that President Francois Hollande would not be opposed to putting the matter to a vote.
"Intervening in Syria can have extraordinarily serious consequences," said Christian Tomuschat, an expert on public international law and former member of the UN Human Rights Committee. In his view, the US and British heads of state reached out to parliament after growing fearful of their own boldness. "That's why Obama and Cameron wanted to spread the responsibility for an intervention to more people," he added.
'Element of reason'
Tomuschat sees a fundamental shift under way, explaining, "In democratic states, there's increasing reflection on whether parliament needs to be involved in decisions about military action."
The human rights expert sees that as a positive development. "It's a moderating element, an element of reason. That's what we saw in the UK."
Political scientist Christian Mölling takes a similar view, saying, "All in all, things are taking a positive course. If parliament has a say, then that represents a democratization of the process. The advantage is that it requires explicit justification as to why a military strike should be undertaken, as in the case of Syria now."
The effect, Mölling stressed, is there is more debate when it comes to whether a given act of war is right or wrong. By including parliament, he believes governments can foster greater support for their security policies among the population at large.
Putting on the brakes
Those opposed to including parliament in such decisions say that it can lead to unnecessary delays when it comes to key security questions.
"Of course military strikes become a thornier issue once parliament gets involved," Tomuschat said. "But that's not a bad thing. An act of war should never be a simple matter."
When it comes to a direct attack on German soil, the government is authorized to react immediately. Parliamentary approval can then come retroactively. And when it comes to sending German forces abroad, parliament has generally issued its approval quickly.
Although Obama, Cameron and Hollande do not require such approval, the act of putting a vote to parliament puts them in an exceedingly difficult position should they decide to go against parliament's wishes.
Putting the question in the hands of parliament also sets a precedent, making it more likely for voters and their elected representatives to demand input on proposed strikes in the future. As such, there are signs that the doctrine of parliamentary approval is on its way to becoming an unwritten law in several of the world's key security players.