I'm not advocating isolationism but engagement where our interests are truly at stake and there's some end game that can realistically be achieved after which, we withdraw.
That "engagement" sounds
awfully transactional. You've already suggested that the US shouldn't be involved because we don't need their oil (which is not true, Persian Gulf nations still make up 16% of oil imports). Your position seems to be "sure, we can sacrifice American lives, but only if we get a bunch of oil out of it!" It is incredibly difficult to see that as a morally sound position.
Plus, the idea of "win today, leave immediately" is unrealistic. That isn't how modern warfare works, and that has to be a consideration
before engaging military action. Too late for that now.
And yet again! Wringing your hands is all well and good, but it doesn't change the fact that withdrawing now will be a disaster for the Kurds and, to a lesser extent, the US.
The Shiites and Sunnis are going to be at each other's throats no matter what we do.
And again, that's just ahistorical nonsense. The Sunnis and Shiites haven't spent the last 1400 years slaughtering each other non-stop. The sectarian conflict is really about the
political conflict between Iran and Saudi Arabia. Iraq didn't have a ton of sectarian tension before the US invasion, in no small part because Hussein hated both Iran and the Saudis. When the US took him out, Iran (90% Shia) started to back Shia groups in Iraq (61% Shia). The conflict is not theological or ethnic, it's about political power.
We're not even talking about a sectarian conflict in northern Syria! It's all political. Assad started the war because he didn't want to be deposed and replaced by a democracy. The US backed pro-democracy rebels to kill ISIL, and to take out another autocrat that backs terrorism and hates Israel. Russia stepped in because Assad is their last ally in the region, and Syria has the only Russian base in the Middle East. Turkey stepped in because they wanted to take out the Kurds.
That's nothing new, by the way. Most sectarian conflicts are really about politics. E.g. in Northern Ireland, the split between Catholics and Protestants is really about English vs Irish control. The IRA wasn't bombing buildings because most Brits don't go to confession, it's because they hated being under British control. In most cases, religion is merely recruited by the political actors to justify the violence. (See
https://www.amazon.com/Fields-Blood-Religion-History-Violence/dp/0307946967)
And again, even with longer conflicts, the "Endless War" claim is complete nonsense. We could have said the same thing about the Chinese and Japanese, the Protestants and Catholics, the FSLN and the Contras, the French and Germans, the list goes on. Enemies yesterday, allies today. It happens over and over.
Oh, and those American lives sure as hell are worth more to their families.
And those Kurdish soldier's lives are worth more to
their families. See how that works?
In case you missed it, American soldiers are a volunteer army. America has had active military engagements since 2001, and anyone who joins the military today is responsible for knowing that there is a very high chance they will be in active combat. (Kurdish soldiers don't really have that luxury, as their homeland is facing an existential threat.)
And since the US spent years relying on the Kurds -- and I might add, after betraying them at the end of the Gulf War in the 1990s -- it is unconscionable to withdraw and leave them twisting in the wind (again). That goes double because Trump
chose to withdraw, knowing that Turkey is planning to attack.
What do you think this is,
Lord of the Rings, where the Big Bad loses and the entire world becomes permanently peaceful overnight?
What you fail to recognize is that
interventions do often work, and that the world is actually becoming more peaceful. The problem isn't with the concept of intervention, it's with the execution. E.g. Western powers had lots of legitimate reasons to push out Assad, they just weren't willing to do what it takes. And part of that is the desire of people (like you) to finish things up in 30 seconds and leave, when that is no longer how the world works.
To put it another way: If keeping 1000 or so US troops (who experience very low casualty rates btw) in northern Syria prevents Turkey from attacking 2 million Kurds, that's actually a highly effective humanitarian intervention -- and a
much better reason to keep those troops there than hoping to get some oil out of the deal.