When we talk to our enemies, we tend to make many of our friends nervous that we will strike a deal at their expense. I guarantee that if talks with Iran get going, before long our European friends will wonder where they fit in to our deals?
Such a policy does not make new friends except at the expense of existing friends and people who deserve to be our friends. In the end, this policy just leads to a net loss of friends.
Is it so hard to keep in mind that some people aren't worthy of being our friends?
UPDATE: Sowell puts it well, writing:
Barack Obama is following a long practice among those on the left of being hard on our allies and soft on our enemies.
So we'll have fewer of the former and more of the latter.