Can the President order assassinations?

While I am displeased by the spinelessness of the Judicial branch when faced with a matter of "national security" these days, ironically enough I do believe it is possible for the President to indirectly authorize the assassination of any person he pleases... without any violation of the Constitution. I'm not saying he SHOULD do this... merely that he can. The political fallout would be what it would be, and Congress could use it's constitutional power to impeach every bit as arbitrarily if they chose to do so... but while it may be politically unsafe for the President, it can be safe for the trigger man.

Here's how it works:

1. The President secretly confers with the trigger man. At this point, the President steps out of matters entirely for the time being.

2. The trigger man does the deed, committing an act that, legally speaking, is murder.

3. Someone charges the man with murder, and he is tried, convicted, and sentenced.

4. The President issues a pardon.

Now, I'm not complaining that Anwar Al-Aulaqi is dead; the fact is, the man most likely needed killing. I'm also not necessarily complaining that the President is getting away with it. However, I am very disappointed with the courts for refusing even to hear the case, basically saying that it is legal for the President to have anybody killed that he wants. They ought to have convicted the people involved in what should be interpreted as an illegal order, forcing the President to use his power to pardon for the exact purpose Alexander Hamilton suggested it should be used years ago. Congress can then sort out whether they think it was appropriately immediately, or the electorate can do so next year.