diff --git a/python/cudf/cudf/core/column/column.py b/python/cudf/cudf/core/column/column.py
index 3b9f917ce8c..bf84b83a5dc 100644
--- a/python/cudf/cudf/core/column/column.py
+++ b/python/cudf/cudf/core/column/column.py
@@ -1346,24 +1346,16 @@ def as_column(arbitrary, nan_as_null=None, dtype=None, length=None):
             arbitrary = arbitrary.astype(dtype)
 
         if arb_dtype.kind == "M":
-            import datetime as dt
 
             time_unit, _ = np.datetime_data(arbitrary.dtype)
-            cast_dtype = time_unit in ("D", "W", "M", "Y") or (
-                len(arbitrary) > 0
-                and (
-                    isinstance(arbitrary[0], str)
-                    or isinstance(arbitrary[0], dt.datetime)
-                )
-            )
+            cast_dtype = time_unit in ("D", "W", "M", "Y")
 
             if cast_dtype:
                 arbitrary = arbitrary.astype(np.dtype("datetime64[s]"))
-            assert arbitrary.dtype.itemsize == 8
 
             buffer = Buffer(arbitrary)
             mask = None
-            if np.any(np.isnat(arbitrary)) or nan_as_null:
+            if nan_as_null:
                 data = as_column(
                     buffer, dtype=arbitrary.dtype, nan_as_null=nan_as_null
                 )