I'm not very knowledgable in ballistics, but I'll try to give my insight.
Actually, we shouldn't question, whether or not iskander can be intercepted (because it can be), but what resources such an interception would tie down.First example. An iskander missile is launched against Patriot PAC-3 battery. Can it be intercepted? Easily.
Second example. The same Iskander is threatening the entire 400km length region behind the front lines, comprising troop concentrations, HQ posts, warehouses, roads, bridges and so on, defended by the very same Patriot PAC-3 battery. Can it be intercepted now? Hardly
And much more batteries would be required.
So you see, having anti-ABM measures doesn't somehow make the missile " silver bullet", but it does increase missile's survivabilty and ties down more SAM batteries in order to increase the chance of successful interception.
I doubt it, if you didn't know already then you should know now that the PAC-3 system has been compromised, the manufacturers of the Iskander-M could easily make a phone call to Beijing and get some critical details of the PAC-3 system.
China is more than willing to get back at the Pentagon for it's historical meddling in Tibet, Taiwan, the South China Sea, and the Daiyou/Senkaku Islands.
You can be skeptical all you want, the Pentagon itself admitted that Chinese hackers compromised most all the air defence systems of the United States including the Pac-3:
"Among more than two dozen major weapons systems whose designs were breached were programs critical to U.S. missile defenses
and combat aircraft and ships, according to a previously undisclosed section of a confidential report prepared for Pentagon leaders by the Defense Science Board.""Experts warn that the electronic intrusions gave China access to advanced technology that could accelerate the development of its weapons systems and weaken the U.S. military advantage in a future conflict."
http://www.washingtonpost.com/world/national-security/confidential-report-lists-us-weapons-system-designs-compromised-by-chinese-cyberspies/2013/05/27/a42c3e1c-c2dd-11e2-8c3b-0b5e9247e8ca_story.htmlA list of the U.S. weapons designs and technologies compromised by hackers
Weapon designs and technologies compromised
The following is reproduced from the nonpublic version of the
Defense Science Board report “Resilient Military Systems and the Advanced Cyber Threat”:
Table 2.2 Expanded partial list of DoD system designs and technologies compromised via cyber exploitation
SYSTEM DESIGNSTerminal High Altitude Area Defense
Patriot Advanced Capability-3
Extended Area Protection and Survivability System (EAPS)
Advanced Harpoon Weapon Control System
Long-term Mine Reconnaissance System
Navy antenna mechanisms
Global Freight Management System
Micro Air Vehicle
Brigade Combat Team ModernizationAegis Ballistic Missile Defense System
USMC Tracked Combat Vehicles
Warfighter Information Network-Tactical (WIN-T)
T700 Family of Engines
Full Authority Digital Engine Controller (FADEC)
UH-60 Black Hawk
AMRAAM (AIM-120 Advanced Medium-Range Air-to-Air Missile)
Affordable Weapons System
Littoral Combat ShipNavy Standard Missile (SM-2,3,6)
F/A and EA-18
Mk54 Light Weight Torpedo
UAV video system
Specific Emitter identification
Dual Use Avionics
Fuze/Munitions safety and development
Electronic Intelligence Processing
Tactical Data Links
Advanced Signal Processing Technologies for Radars
Nanostructured Metal Matrix Composite for Light Weight Ballistic Armor
Vision-aided Urban Navigation & Collision Avoidance for Class I Unmanned Air Vehicles (UAV)
Space Surveillance Telescope
IR Search and Track systems
Electronic Warfare systems
Electromagnetic Aircraft Launch
Side Scan sonar
Mode 5 IFF
Export Control, ITAR, Distribution Statement B,C,D Technical Information
CAD drawings, 3D models, schematics
Vendor/supply chain data
PII (email addresses, SSN, credit card numbers, passwords, etc.)
Attendee lists for program reviews and meetings
...Your quick to down play Beijing selling secrets of US weapon systems, well it looks like Beijing sold some critical intel on the PAC-3 to Iran: