Proper syntax for "CASE WHEN ... THEN ... DELETE ... END" in SQLite triggers?

Proper syntax for "CASE WHEN ... THEN ... DELETE ... END" in SQLite triggers?

I'm trying to figure out how to put a delete statement inside a
conditional in an SQLite trigger.
I've come up with this code:
CREATE TRIGGER mytrigger
BEFORE INSERT ON mytable
BEGIN
SELECT CASE WHEN
1 == 1
THEN
DELETE FROM mytable
END;
END;
But it fails with:
Error: near "DELETE": syntax error
If I replace DELETE FROM mytable with RAISE(FAIL, "mytrigger was
activated"), it compiles fine.