What do the rules mean when they say that declaring an attack is an effect?
A. This was an error. Declarations such as declaring attacks and declaring interceptions are not effects. Declarations can be responded to, but they don’t occur as parts of sequences of effects. Players can respond to a declaration of an attack with other effects, but the attack is considered to have started as soon as it has been declared, so many effects that cannot be used during an attack cannot be used in response to a declaration of attack. The attack itself is not an effect, so it cannot be canceled. See The Steps of an Attack for the stages involved in an attack.
