Based on your experience, is there any reason to believe that USA military as it currently exists could ever be more successful at achieving military objectives in any similar conflict?
I am probably not qualified to answer that, but I'll give you my take.
The US Marine Corps can do anything it sets its mind to. Marines are an amazing and rare breed of people with a culture to boot. To this day, outside of SOCOM, they are one of the only fighting forces that I know of that continue the legacy, lifestyle, and traditions of a warrior culture. In this capacity, yes, I think if you cry havoc and let slip the dogs of war they will do exactly what they are meant to do with zeal and tenacity.
On the other hand, I think the Marine Corps is bound by tricky circumstances, including in Afghanistan. When guerrilla warfare becomes the standard a uniformed military is at a strategic disadvantage. We are bound to things like the Law of Land and Warfare and the Geneva Convention while the enemy is not. They'll blow up a truck in the middle of a convoy and start firing on your position as you try to rescue your friends from burning alive. They'll plant multi-decompression IED's which explode after having been stepped on multiple times because they know watching your best friend or squad leader getting blown up is a shattering experience. They'll have you chase them through a town, backlaying IED's in buildings that you fought from because they know when they really bring the heat and you retreat that you'll go places that you think you've already cleared as safe. They'll pick fights in crowded markets because they know that having to assess a crowd of targets and picking the wrong target is damning both personally and in PR. They'll send kids to fuck with you, throw rocks at your helmet so you take your eyes off your surroundings -- and they know because the folks at home will ask questions that you won't do anything.
The Taliban, and other groups like them, know that folks back home in America are always watching and forming opinions -- many of them in their favor. They know that the more frustrating they make the war, and the harder and more drawn out they make it the more frustrated the American people become. They don't really need to do much; blow up a bridge here, destroy some cellphone towers, set off a couple IED's in crowded spaces, etc... It's the epitome of slow and steady wins the race.
Can a war be won against such people? I think so. The British beat the IRA into submission and they used most of the tactics the Taliban/ISIS/Al Queda use. The difference is they had popular support and it was much closer to home.
Thanks for the answer. I confess I don't see why any similarly-situated opponent would eschew any of those problematic tactics. If we can't handle those we can't in good conscience go to war.
Your impression of the Northern Ireland peace process seems wildly at odds with my recollection. The various Republican and Unionist groups killed and injured more people than the government did. The Provos forced the other parties to the negotiating table with the Docklands and Manchester bombings, and the resulting Good Friday agreement was approved by 97% of Catholic voters because it established local government and made it possible for Ireland to be reunited based on future votes. IRA was no more "beaten into submission" than Taliban were.
On 9 February 1996 a statement from the Army Council was delivered to the Irish national broadcaster Raidió Teilifís Éireann announcing the end of the ceasefire, and just over 90 minutes later the Docklands bombing killed two people and caused an estimated £100–150 million damage to some of London's more expensive commercial property.[183][184] Three weeks later the British and Irish governments issued a joint statement announcing multi-party talks would begin on 10 June, with Sinn Féin excluded unless the IRA called a new ceasefire.[185] The IRA's campaign continued with the Manchester bombing on 15 June, which injured over 200 people and caused an estimated £400 million of damage to the city centre.[186] Attacks were mostly in England apart from the Osnabrück mortar attack on a British Army base in Germany.[185][187] The IRA's first attack in Northern Ireland since the end of the ceasefire was not until October 1996, when the Thiepval barracks bombing killed a British soldier.[188] In February 1997 an IRA sniper team killed Lance Bombadier Stephen Restorick, the last British soldier to be killed by the IRA.[189]
Following the May 1997 UK general election Major was replaced as prime minister by Tony Blair of the Labour Party.[190] The new Secretary of State for Northern Ireland, Mo Mowlam, had announced prior to the election she would be willing to include Sinn Féin in multi-party talks without prior decommissioning of weapons within two months of an IRA ceasefire.[190] After the IRA declared a new ceasefire in July 1997, Sinn Féin was admitted into multi-party talks, which produced the Good Friday Agreement in April 1998.[191][192]