President Obama was elected because he promised Americans that he would end what he once called the "dumb war" in Iraq and bring the soldiers back from Afghanistan. As a candidate, Obama spoke to his voters' hearts when he questioned the purpose of those two wars.

Of course, the US boasted - and still boasts - the most modern and powerful military in the world. But even that power can become overstretched when it has to fight on a number of different fronts around the world. Even the Cold Warriors in Congress know that there are some problems that can't be solved militarily, not even by the US.

But all these insights are being dismissed in Washington. Politicians, currently in campaign mode, are making patriotic speeches all over the country: the "Islamic State" must be destroyed. CNN, Fox News, and the rest of the "news networks" - really businesses - bluster about how America is "the greatest power that human history has ever seen." On US flights, captains greet military officers with special enthusiasm. "Men and women in uniform," as they're called, are allowed to board flights first, along with the disabled and women with small children.

A nation marked by war

But this wave of patriotism may not last. Americans are tired of war, even though the majority of them currently support the military operation on the Syrian-Iraqi border. But should the mission drag on, the mood is likely to change quickly.

Already those politicians who opposed the withdrawal from Afghanistan, such as Senator John McCain, have become more vocal. Washington think tanks are discussing whether allies like Germany or other NATO members might be willing to send combat troops to Afghanistan beyond 2014. Al Qaeda has been weakened, they point out, but is far from beaten. Certainly not in neighboring Pakistan. And then there are the Islamists in Yemen, who also need to be held in check, the political advisors warn. Moreover we shouldn't forget Somalia, which needs the West's support now more than ever.

Retired air force general Charles Wald, who coordinated the airstrikes against the Taliban in Afghanistan in 2001, recently summed it up well: America is facing a period of constant war. Other generals agree with him - Americans alive today will never experience of true peace.

Keeping distance, yes. Staying out of it: impossible.

Is this what Osama Bin Laden wanted all along? Did the Islamists, by whatever name they currently go, lose all the battles, but win the war against the West after all? No country, not even a superpower like the US, wants to live in a state of permanent war. At some point it will get tired, worn out, over-burdened.

President Obama seems to sense that. In his latest address to the nation, he underlined the important difference between the fight against the "Islamic State" and the wars in Iraq and Afghanistan - the US will not be sending any ground troops. But what if IS turns out to be more resilient than expected? What if the airstrikes and the Kurdish and Iraqi fighters aren't enough to beat the Islamic State? Will the US give up? Unlikely. Will Washington be forced to send combat troops after all? President Obama will probably not have to make that decision - but the next president will. And maybe the president after that too.