Setting renderQueue doesn't appear to change draw order

This seems like such a simple thing, judging by the Unity script reference and examples here, but I can't get render queues (set in the material) to work at all. I've set up a very simple scene with two boxes and a camera, one box behind the other (see picture).

Then, I added a script that changes the render queue of the two materials, flipping the queue order. I do a debug afterwards which verifies that the renderQueue value has been changed. The only problem is that the draw order doesn't change - the nearer cube is always rendered over the far cube.

I've included my code below. As you can see from the comments, I tried setting the renderQueue in the renderer.material, sharedMaterial, and the material asset directly, and in all cases the renderQueue value changes but the render order does not. What am I missing here?

 using UnityEngine;
 using System.Collections;

 public class ChangeMaterialQueueOrder : MonoBehaviour {
 
 public GameObject go1;
 public GameObject go2;
 
 public Material m1;
 public Material m2;
 
 // Update is called once per frame
 void Update () {
     if (Input.GetKeyDown(KeyCode.F))
     {
         Debug.Log("Changing 1 to back");
         //go1.renderer.sharedMaterial.renderQueue = 1001;
         //go2.renderer.sharedMaterial.renderQueue = 1002;
         //go1.renderer.material.renderQueue = 1001;
         //go2.renderer.material.renderQueue = 1002;
         m1.renderQueue = 1001;
         m2.renderQueue = 1002;
         //Debug.Log("Render queue changed; go1 renderqueue now " + go1.renderer.material.renderQueue);
         Debug.Log("Render queue changed; m1 renderqueue now " + m1.renderQueue);
     }
     if (Input.GetKeyDown(KeyCode.G))
     {
         Debug.Log("Changing 1 to front");
         //go1.renderer.sharedMaterial.renderQueue = 1002;
         //go2.renderer.sharedMaterial.renderQueue = 1001;
         //go1.renderer.material.renderQueue = 1002;
         //go2.renderer.material.renderQueue = 1001;
         m1.renderQueue = 1002;
         m2.renderQueue = 1001;
         //Debug.Log("Render queue changed; go1 renderqueue now " + go1.renderer.material.renderQueue);
         Debug.Log("Render queue changed; m1 renderqueue now " + m1.renderQueue);
     }
 }
 }

P.S.: I'm using Unity Pro.