Congress pushes the Army to modernize/buy armored vehicles...which leaves the Marine Corps in a quandary...

via Inverse.com

The United States has run up against enemy tanks in the early stages of both Iraq wars, but an uneven fight where the America’s military had command of the air (planes beat tanks in the big rock-paper-scissors of combat, generally) isn’t really a good test of its tank capabilities the way that a land war with Russia would be.
In such a fight, Congress is worried that the current vehicles, like the M1 Abrams MBT — there’s approximately 9,000 of them at $5 million a tank — won’t quite cut it. The M1 has been in service since 1980, and until now the military’s policy has been to keep slapping upgrades and new technology on the same platform, basically across the board. In the future, though, it’ll be much easier to incorporate new technology on a platform specifically designed for it, and the military will need an entirely new main battle tank in the future.
As Breaking Defense reports, the Army already had plans for a successor to the Abrams, first in the “Ground Combat Vehicle” program (which it ended in 2013), and currently with the Next Generation Combat Vehicle program, which wants to have a new design for a heavy vehicle that acts as a mothership for packs of drones and unmanned ground vehicles. But the HASC’s message is clear: hurry up.

Story here. 

ACV contestants aboard ship

Read the entire article to get the flavor of things but consider this....The US Army has gone from the M1A2, M1A2 SEP, M1A2 SEP v2, M1A2 SEP v3, and are working on the M1A3 for introduction around the 2020 time frame.

Meanwhile the USMC will make a decision on the final winner of the ACV in 2018 with full scale production hopefully in 2019.

The USMC M1A1?  It will soldier on.  While the US Army will have gone thru (counting the base M1A2) four iterations of the M1A2 and will be working toward the M1A3 the USMC will be soldering on with the M1A1.

That my friends places the Marine Corps on the horns of a dilemma.

The solution (from my chair) are a series of uncomfortable choices that introduce risk into the equation if we ever have to do another "800 mile" cross country run.

US Army Stryker Mobile Gun System

Solution 1:  Go with the Mobile Gun Solution.

LVT-A5 AMTANK at Saipan

The Tank community would howl but a possible solution is to go the Mobile Gun System route.  Marine Corps Tankers take pride in supporting the infantry, but they're trained to destroy tanks.  Going to a MGS will require a change in culture, but should be doable.  Tank killing would fall to properly equipped
ACVs designated as anti-tank variants and equipped with TOW or a similar missile.  MGS variants of the ACV would take care of pillboxes, fortifications, obstacles etc...An immediate advantage is that they would be able to swim ashore and would be a nod to history.  AMTANKS was once a thing and there might be a few old skool Marines still hanging around that would cheer its return.

USMC tanks in Norway

Solution 2:  Soldier on with the M1A1.

It could be argued that the M1A1 is "good enough" for Marine Corps purposes. Some would say that modest upgrades will keep it highly capable into the future.  Some would say that the real problem is in having enough of these vehicles in fighting shape where and when we need them is more of a pressing problem than actually keeping pace with the Army and updating them.

BAE Modernized M8

Solution 3.  Follow the Army Airborne and go light tank.

I have no idea how Marine Tankers would react to this idea.  I don't think you'll see a potential USMC Light Tank variant being dropped out the back of C-130's, but the weight saving aboard ship might see bigger detachments.  I assume that the Airborne boys would want their vehicle to be as fuel efficient as possible so that also yields benefits unrealized, and since they're going for a large caliber cannon (I believe 120mm but it could be a 105) it might be capable of engaging MBTs. NOTE:  A quick Google search reveals that the BAE entrant has the 105 while the General Dynamics sports the 120. Regardless we could see brand new opportunities open up.  Amphibious raids with platoons of Light tanks escorting ACVs?  SOCOM would love that for some of their raids and even if we're acting in a supporting role, that kind of firepower would be welcome.  But there is always a downside.  For the light tank option you're looking at a vehicle that just can't take the hits that a MBT can.  Instead of leading the assault the light tanks will be back providing supporting fire to infantry assaulting...alone.

Solution 4.  No tanks.

This is the solution that the Marine Corps once appeared to be pursuing (and still might for all I know).  Tank strength in the Marine Corps has been drastically cut (misplaced an excellent article on it...I'll try and find it) and many in the Tank Community were becoming alarmed.  Recently we've heard of some planned upgrades for the M1A1 so perhaps those plans were never real and only rumors.  Quite honestly I see no upsides to this.  Direct fire will always be a necessity on the battlefield.  Any weather, always on hand firepower is a must have.

My guess on how this will play out?

I don't see a "AMTANK" coming anytime soon.  While I believe this is the best option if we can't have a real tank, and while being able to swim to shore with the assault element and standardizing or "necking down" to one armored vehicle type makes all kind of sense I just don't see it happening.  We don't have the money.  A light tank option?  Don't see that either.  I've already pointed out the advantages and operating a common vehicle with the Army is a money saver in so many ways I just don't think the Marine Corps is culturally ready to accept a light tank (yeah I know...an AMTANK based on the ACV would just be a LARGE light tank but it swims so its in a different category).

My guess is that this can gets kicked down the road.  The M1A1 in some modestly upgraded form will soldier on till around 2030 or so.  I expect the Marine Corps to totally skip the M1A2 gen of tanks and wait and see what the M1A3 offers.  If the updates are adequate, no breakthrough in tank technology is achieved then we could see the Marine Corps going till 2040-2050 with a tank that was first conceived in the 1970s.