Blitz Touch Move Rule In a "friendly" blitz game I got into an argument with my opponent in the following scenario:

My opponent's knight was pinned to his king. He did not notice and touched his knight to move it. I became excited and before he had a chance to press his clock, I took his king.

The question is: by official rules does my opponent lose the instant he touches the knight? (Making any action taken after this instant irrelevant?) Or does he need to "complete" the move by pressing the clock?
The touch-move rule never compels you to make an illegal move. It may compel you to make a stupid move, but not an illegal one. For example, you'd be forced to move a knight that's pinned against your queen and lose your queen as a result, but you'll never be compelled to move an absolutely pinned knight which would put you in check.

See this related question for more discussion, but I'll quote here the relevant FIDE rule here:


  4.5 If none of the pieces touched in accordance with Article 4.3 or
  Article 4.4 can be moved or captured, the player may make any legal
  move