here is a proverb in old Europe that goes something like this: may God protect me from my friends so I can fend off my enemies.

One has to look at many situations in the world to acknowledge that friends and allies of the United States can create problems that are larger than those posed by enemies and potential adversaries.

In Afghanistan, President Hamid Karzai refuses to sign a security agreement with the U.S. that would pave the way for a withdrawal of American troops from that country, at the end of an undeclared and messy war that in 12 long years has cost America $700 billion and 4,310 casualties.

The bilateral security agreement that has already been negotiated would allow NATO to maintain 10,000 troops after the bulk of its troops were withdrawn at the end of 2014. This is now up in the air. No matter what, the main withdrawal will take place.

In his State of the Union speech President Obama said clearly: “By the end of this year, America’s longest war will finally be over.” Can we believe the president? Afghanistan is worthless as the ground of a military fight, but for too long Americans have been told that the U.S. cannot give up its counter terrorism operations to defeat Al Qaeda, in Afghanistan and elsewhere.

The Afghan chief of state seems determined to frustrate the American decision to salvage with honor the situation in Afghanistan. And yet, he should know that his refusal to sign will mean the end of U.S. military aid and consequently the collapse of the Afghan army and almost certainly of the Afghan government, and with it the entire country.

Should Americans shed tears for the obstreperous Afghan president who has recently added insult to injury by releasing 65 detainees from a military prison, disregarding American objections over the fact that many of the detainees were guilty of killing American troops and Afghan civilians? There were no court trials and the detainees were freed by a Karzai-appointed commission.

There is talk that Karzai is secretly negotiating with the Taliban. This could explain his behavior and his maneuvering to save his neck the day he is longer president. In fact, however, there is precious little chance that the Taliban will work out a deal with the outgoing president.

The Taliban can afford to wait for the moment when they will try and dictate their conditions for becoming part of the government. On the other hand, the possibility of the Taliban taking over completely does put pressure on Karzai to cast himself as someone who resisted acting as an American puppet.

One thing is fairly certain, that after Karzai the conflict in Afghanistan will go on. Should Americans shed tears for Karzai? Once the U.S. troops are out of that country, the survival of the wily president is a minor matter. The fact will remain that the U.S. will not let go insofar as the fight against al Qaeda is concerned. Other strategies will have to be decided and brought to bear on the enemies of America.

Unconventional conflicts against terrorists and irregular forces in the world will have to be fought without the application of massive military force that the Un.S. is able to display. There are no military solutions in Afghanistan and other places where friendly forces turn out to be something different from great friends.

Israel is another example of a great friend that causes many pains. Just witness the excruciating problems that Secretary of State John Kerry is having trying to mediate the Israeli-Palestinian question. But that is a much more complex chapter that will continue to bedevil America.