[MarkL]

Remember, Malfoy actually disarmed him. Malfoy used expelliarmus on Dumbledore the moment he arrived at the tower. Malfoy actually did win it by force, just by getting the drop on him.

But my point was that he WANTED to be defeated in a duel.

Mark

[Obi-Wandreas]

Quite the opposite.

You'll recall, that by asking Snape to kill him, and making sure that Snape was the one to do it, Dumbledore was trying to insure that he was never defeated.

If Snape had killed Dumbledore before Malfoy got to him, Dumbledore would have remained the master of the Elder Wand. Since Snape was just carrying out his orders, it wouldn't be a defeat for him. The wand's power would have died with him.

Malfoy, by getting the drop on him, gained the Elder Wand for himself. Thankfully, however, he never knew it until it was too late.