This Doesn't Make Sense

Here's something I don't understand.

1. The Unites States through Lockheed Martin is selling 100 fighter jets to Turkey. This quote is from LA Times article about it - "The Turkish air force already has 215 F-16 fighter planes and plans to buy 100 of Lockheed Martin's new F-35 Joint Strike Fighter as well, in a deal estimated at $10.7 billion over the next 15 years."

2. I just read in The Week that two U.S. F-16 figher jets recently crossed into Turkish airspace while flying over Iraq. The Turks did not like this and their Prime Minister said, "We warned them not to repeat this. If this happens again, if this takes a different dimension, what we will do is obvious." He didn't say what "obvious" meant, but it is clearly a threat.

WHY WOULD WE SELL FIGHTER JETS TO A COUNTRY MAKING THREATS AGAINST US????????????