Can Defy counter spells like Cleave when they are played outside of showdowns (e.g., at a player's base)?

Ruling: Yes, Defy can be used to counter spells like Cleave even when they are played outside of showdowns, such as at a player's base.

Nuances:

• Playing spells before entering showdown can help avoid other counter-effects like Gust, which can only be played at battlegrounds
• Playing spells pre-combat allows you to know if they will be countered by Defy before committing to combat, helping you decide whether the combat is still viable
• Units that gain bonuses from Assault will have those bonuses already applied if the spell is played before the showdown, making them immune to certain counters that check current Might values