Hopefully you saw Fahrenheit 9/11, the movie by Michael Moore that was prominent in 2004. His main topic throughout the movie was to explore cronyism and how that created the war in Iraq. The main example is the laundry list of business ties between the Administration, the Saudi royalty and even to the bin Laden family. That most of the Administration has ties to the Oil Industry (both GW and GHW Bush owned oil companies, VP Cheney was the CEO of Halliburton, Chevron named an oil tanker for Condoleeza Rice, etc) figured heavily in this movie.
In one segment Moore talked about the oil in Central Asia and the U.S. plan for bringing that oil to market. The Central Asia oil has been a matter of power play for several years, and it's land-locked position that isn't easily accessible makes it difficult to "extract" and sell on the market. Taking it in one direction, you'd be going through Russia. Another direction and you're going across Siberia and then the port is in the arctic and probably locked in by ice. And to the south are steep mountains, some of the highest in the world. Also to the south is Iran, a sworn enemy of the U.S.
The chosen U.S. route was through Afghanistan. The U.S. has pushed for this route since the 1990's. The problem was, neither Afghanistan nor Pakistan were terribly friendly to the U.S. The Taliban was in control, and Pakistan was very friendly with the Taliban. It didn't make any difference that during the 1980's the U.S. worked closely with Pakistan and the people who became the Taliban. In the 1980's the menace was Russia's invasion of Afghanistan, and the U.S. effort to drive Russia out, which meant a secret operation supplying the mujahadeen (as they were known then) with arms and training. By the 1990's that was long in the past, and U.S. policy had shifted away. Even so the Taliban government visited the U.S., as Michael Moore documented, working to negotiate both the opium poppy eradication as well as the pipeline deal.
BTW, since the toppling of the Taliban government, opium poppy production has sprung back to pre-Taliban levels.
In any case there was an existing plan to run an oil pipeline through Afghanistan. And you can imagine the big question in U.S. and oil industry planning -- how the heck do we get access to Afghanistan? Essentially that country had become enemy territory.
Conveniently the September 11, 2001 attack provided the needed excuse. The culprits were in Afghanistan, which gave us all the excuse in the world to invade that country, topple its government, etc.
And, now, conveniently the path was clear. Afghanistan was no longer essentially enemy territory. Further, in the process of making war on Afghanistan the U.S. established bases and cooperation with several Central Asian countries. These countries had been carved out of the former Soviet Union after its collapse in the early 1990's.
A nagging question is whether the September 11, 2001 attack was merely a coincidence, or whether some behind the scenes conspiracy created it? There's enough connections there to make one ponder. The Bush family had ties with the bin Laden family, to the point that one of the bin Laden cousins bailed George W Bush out of at least one of his failed businesses. And there was the pre-existing plan for a pipeline through Afghanistan, and coincidentally the major players in creating that plan are now major players in both the Afghanistan government and the U.S. relationship with Afghanistan.
But there isn't enough proven data to truly connect the attack to any behind the scenes conspiracy. So we'll just leave that question dangling out there.
What's of interest now is this article: India to join Turkmenistan gas pipeline
It discusses two different pipeline projects to bring Natural Gas to "market". One is the US-backed Turkmenistan-Afghanistan-Pakistan (TAP) while the other is the Iran-Pakistan-India (IPI).
This appears to be part of the larger geopolitics power struggle. The different sources of these two pipelines is interesting. Iran being an U.S. enemy at this moment makes this statement interesting:
Moreover, unlike IPI, the project does not run the risk of being blacklisted for participation by US and European financiers and companies. The US has been encouraging Pakistan to abandon the IPI project and consider TAP for meeting its gas needs.
Blacklisted?? This isn't explained, but clearly the official relationship with Iran is problematic for many countries. But Pakistan probably has a lot of cooperation with Iran, given they share a long border and probably have common cultural elements. But to the U.S. and the "west" Iran is a pariah, being controlled by fundamentalists who are opposed to the western powers.