AFNetworking-2 waitUntilFinished not working

I know there is another similar question, but it's for an older version of AFNetworking, and doesn't really answer it anyway.

I have the following code:

AFHTTPRequestOperationManager* manager = [AFHTTPRequestOperationManager manager];
manager.securityPolicy.allowInvalidCertificates = YES;
manager.requestSerializer = [AFJSONRequestSerializer serializer];
[manager.requestSerializer setAuthorizationHeaderFieldWithUsername: currentUser() password: currentPassword()];
__block NSDictionary* response = nil;
AFHTTPRequestOperation* operation = [manager
    GET: @"https://10.20.30.40:8765/foobar"
    parameters: [NSDictionary dictionary]
    success:^(AFHTTPRequestOperation* operation, id responseObject){
        response = responseObject;
        NSLog(@"response (block): %@", response);
    }
    failure:^(AFHTTPRequestOperation* operation, NSError* error){
        NSLog(@"Error: %@", error);}
];
[operation waitUntilFinished];
NSLog(@"response: %@", response);
...

If I run this, what I'll see in my log is:

2013-12-09 09:26:20.105 myValve[409:60b] response: (null)
2013-12-09 09:26:20.202 myValve[409:60b] response (block): {
    F00005 = "";
    F00008 = "";
    F00013 = "";
}

The NSLog that is after the waitUntilFinished fires first. I expected it to fire second. What am I missing?