This story on The New York Times' web site, about the slaying of a political candidate in Iraq, carries this headline:

Iraq Insurgents Execute Captive Candidate as Election Day Nears

"Execute?" Are they for real?

Here's the sixth definition of the word "execute:"

To put to death, especially by carrying out a lawful sentence.

How about using the word "assassinate," which has this definition:

To murder (a prominent person) by surprise attack, as for political reasons.

Unless, of course, the headline writer thinks the terrorists were carrying out a lawful sentence.