DING!DING!DING!DING!!! WE HAVE A WINNER!!!
"Rant" (not necessarily directed at you!):
I agreed with the view of "competing pipelines" causing much of this trouble for a long time, and I'm sure that still holds with respect to Saudi vs. Iran, with Europe probably favoring the Saudi pipeline too (less chance of Putin being able to exert leverage on flow through it.) But other than Iran being a useful tool for Putin (which may blow up in his face someday), and the US having a somewhat / sometimes useful alliance with Saudi, as well as likely not wishing Europe to be subject to Putin's leverage, there is not economic much upside for the US or Russia to see either pipeline be built. The US might not oppose the Israeli pipeline -- I suspect it's costs will be very high, mitigating its detriments to the US oil industry -- but I bet we are not very actively pushing it along, either.
Of course there is some benefit to the US in terms of geopolitical strategy to not having Europe potentially blackmailed for gas by Putin, but, that is only one factor.
Further... I rather strongly suspect the Russkis are playing the Iranians for fools -- helping them just enough to keep their alliance going, but not actually forcefully pushing to an outcome whereby the pipeline Iran wants gets built through Syria.
I suspect Trump has seen through this, and either thinks it's all pretty sick, or concludes that the Saudis (and their allies) plus the Russians, Iranians, and local discontent, all add up to turmoil the US has no need to assist in the forment of. Or, both. In any event, his disinclination towards unnecessary foreign involvements is (mostly) a good instinct. However, there HAS been (and still remains a bit of) ISIS to contend with, there is Turkey looking like it is going to be a big time problem, and... contrary to the view of many here on FR, there are VERY solid reasons dating back as far as WW1 why chem weapon proliferation and usage just HAS to be met head on. It is NOT in the same category as other horrors in other places and times (as awful as many of those horrors are), and the fact we ("the West") have abrogated that responsibility in some cases of chem warfare does NOT mean we were right to do so.
Nor have the uses of chem weapons in Syria been limited to a couple of "headline" incidents which (at least if looked at superficially) could have been false flag ops. The US report makes clear Assad has been using chem weapons in many smaller casualty attacks since the Russians (and good 'ol Kerry) claimed Syria was free from such. This is in some respects a separate issue: Chem weapons are not (at least @ present) the reason we are assisting the Kurds.
But, back to our President's dilemma: Unfortunately, it'd be pretty tough for even Trump to go on TV and announce that the US assisted in creating prolonged turmoil in Syria resulting in hundreds of thousands of deaths... ...to help block a pipeline and gain geopolitical advantage. (That's actually a too harsh view & highly oversimplified -- perhaps I can address it further someday.) Such a statement would badly damage our country.
There is one other question I've mentioned on FR before, but not for a while, and not quite in enough detail, perhaps. It begins with another question: Coldly setting aside the Syrian lives lost, how much has the Syrian conflict cost the West, and Saudi Arabia and it's allies? There are the non-Syrian "Allies"' lives lost, the refugee problems, Russia again prowling about the ME, and would anyone here have even a rough guess as to the price of all the military hardware and operations expended on the anti-Assad side, as well as ops vs. ISIS? Assign / consider all as economic costs.
Now, take that figure and add the projected cost of the Saudi-backed pipeline and operational costs (including likely security needs), for, say, the next 20 years, and compare that total to the cost of a tanker fleet to do the job(any new ships needed and operational costs for such.)
How do these costs compare? If one has a soul, they can try to factor in the death and destruction in Syria, too.
I find it hard to believe that with the above taken into account, the tanker fleet does not make sense. Why not build it?
With both the Iranian pipeline and a Saudi(?) tanker fleet operating, plus continued US innovation / production, and one would presume a recovery in Venezuela sooner or later, I will hazard a guess that global petro prices would be driven down to the point Saudi's revenue will fall to unbearable (for them) levels. This despite their higher export quantities.
I was trying to be subtle and spur some thought.