LL Rule 2.0 Definitions
OBSTRUCTION is the act of a fielder who, while not in possession of the ball, impedes the progress of any runner. A fake tag is considered obstruction. (NOTE Obstruction shall be called on a defensive player who blocks off a base, base line or home plate from a base runner while not in possession of the ball.
ASA Rules Supplement 36-Obstruction
In past years, coaches taught their player to block the base, catch the ball and make the tag. Now defensive players must catch the ball, block the base and then make the tag.
USSSA Clarification & Interpretation Topics Version 7
If a defensive player is blocking the base or base path without the ball, this is impeding the progress of the runner and is obstruction. After the fielder has the ball, she can block the base and make the tag. It is obstruction if the player blocks the base, catches the ball, and makes the tag.
Just wanted to clarify that the great play made by that catcher in the other current thread would clearly be obstruction under some rules sets. Obviously LL wouldn't apply but is very realistic to be playing ASA or USSSA ball.
You cant selectively take the section of the clarification which fits your personal interpretation of the rule. If you had included the brief section just ahead of your USSSA cut and paste it says exactly what every other rule book says regarding obstruction.
Obstruction is the act of a fielder:
Not in possession of the ball or
Not in the act of fielding a batted ball
which hinders a batter or runner. The act may be intentional or unintentional.
As Ajay posted, there are 2 requirements that BOTH have to be met in order to have obstruction. A fielder not in possession of the ball AND hinders the runner. Until the runner is actually impeded in some way there is nothing to call.