diff --git a/src/orient2d.js b/src/orient2d.js
index 312017a..dc0816b 100644
--- a/src/orient2d.js
+++ b/src/orient2d.js
@@ -57,8 +57,6 @@ export function orient2d(ax, ay, bx, by, cx, cy) {
     const detright = (ax - cx) * (by - cy);
     const det = detleft - detright;
 
-    if (detleft === 0 || detright === 0 || (detleft > 0) !== (detright > 0)) return det;
-
     const detsum = Math.abs(detleft + detright);
     if (Math.abs(det) >= ccwerrboundA * detsum) return det;