This has been a source of discussion, but let's jump in: 

 

With a runner on first base, the right-handed pitcher is in the set position. The pitcher executes the "jump move" but decides not the throw over to first base. What does the umpire do?

 

(For a right handed pitcher, the jump move is a pickoff move to first base where the pitcher first moves his pivot foot (right foot) in the direction of third base and then makes a legal step toward first base with his non-pivot foot (the front, left foot) -- and does so in one continuous motion without interruption).

 

A) This is legal since the pitcher first disengaged his pivot foot from its original place on the rubber. He is now an infielder and is not required to throw.

 

B) This is a balk and the runner should be awarded second base.