@JeremyECrawford Rules question, Sir… Can a caster cast a spell like Shield or Counterspell, if there is no attack made against them or a spell to counter?
— Keith (@Glytched) December 6, 2017
A reaction spell that has a defined trigger can be cast only in response to that trigger. If that trigger doesn't happen, you can't cast the spell. #DnD https://t.co/d8qoJfo89F
— Jeremy Crawford (@JeremyECrawford) December 7, 2017