> One major theme in the ongoing US-Russia conflict over the past decade-plus (dating back to at least 2008) is a fight over who gets to sell oil and gas to Europe.
No, it wasn't. America wasn't pushing to sell to Europe, and Europe was becoming more and more reliant on Russian and Asian gas. The shift to American gas (and every other country they can get it from) happened after Russia invaded Ukraine and then shut off the taps when Europe instituted sanctions.
Iranian sanctions were mostly inertial, but have now turned out to be good considering that Iran is negotiating nuclear tech in exchange for shipping weapons to Russia.
My view is that the split with Putin really started in late 2003, when Putin rejected an Exxon offer to take a controlling stake in Russian oil via the purchase of Yukos, and then jailed Khodorkosky (who was close to various USA interests) on tax evasion charges. Prior to that, Putin got a lot of favorable mention in the US press, he visited GW Bush in Texas, was an ally in the 'war on Terror' etc. If Putin had taken the offer, Russia would have become more like Saudi Arabia - i.e. part of the petrodollar recycling system. Putin's domestic popularity in Russia since then is largely due to the fact he redirected oil money to domestic economic growth and military reconstruction, rather than to Wall Street funds.
Everything since then has been one pipeline war after another, from the perspective of energy deals at least. Georgia 2008, for example, was "not a pipeline war!" according to the Guardian (meaning a lot of people were saying it was, and they were pushing back). Note how the 2006 BTC pipeline route (Baku-Azerbaijan-Turkey) was chosen to bypass Russia?
After that, there were the two competing pipeline deals in Syria, c. 2009-2010. One was a Russia-Iran deal, one was a Qatar-Saudi-USA deal. In 2010, Assad took the Russia-Iran offer, and in 2011, Obama's government OKed a CIA destabilization-and-regime change program in Syria. If Syria had taken the other offer, I doubt that would have happened. This Ukraine war is just more of the same (plus, a new Cold War is good for military procurement budgets).
Of course, energy geopolitics isn't the only issue, but anyone who has read Steve Coll's "Private Empire: ExxonMobil and American Power", or Daniel Yergin's "The Prize: The Epic Quest for Oil, Money, and Power" will recognize it's often the central reason for international conflicts.
As far as the clearly reprehensible human rights record of Putin being the reason for the conflict, that's laughable - just look at Mohammed bin "Bone Saw" Salman in Saudi Arabia, or the Yemen war. Now if MBS pulled out of Wall Street and ended the Saudi roll in petrodollar recycling, then we'd be hearing about the need for regime change. And if Putin and Assad had signed up for the petrodollar program, they'd be lauded as democratic reformers, and the Ukraine invasion would portrayed in the US media as a necessary action to dismantle neo-Nazi militias (see Yemen, again).
There are many things that can lead to international conflict and war: Energy, influence, territory, etc.
The Ukraine war is primarily territorial at any cost, as can be seen by Russia's willingness to lose Europe as a trading partner (including the now uselessness of most of its pipeline network since it was primarily directed to Europe), as well as almost all of Russia's complete surprise (including top government elites and the army brass) at the invasion in the first place. Belligerence from resource grievances fester for decades, and are telegraphed well in advance since pretty much the entire government will be on board before they start. It's also fairly obvious with Putin's continued nationalist rhetoric about reuniting "little Russia", and his continued rhetorical grievances with the West for over a decade. This is an obsession, planned in a way that nails everyone's colors to the mast. The causes for this war are primarily ideological (rebuilding Russia into its fabled great empire), not economic or strategic (although those do play minor roles, as always).
> My view is that the split with Putin really started in late 2003
It started with (or maybe earlier than, but crystallized with) the NATO-Yugoslav war in 1999 (and this was widely and fairly specifically noted at the time.) Certain factions of the American political establishment may have been in denial about that rift until 2003, though.
No, it wasn't. America wasn't pushing to sell to Europe, and Europe was becoming more and more reliant on Russian and Asian gas. The shift to American gas (and every other country they can get it from) happened after Russia invaded Ukraine and then shut off the taps when Europe instituted sanctions.
Iranian sanctions were mostly inertial, but have now turned out to be good considering that Iran is negotiating nuclear tech in exchange for shipping weapons to Russia.