It is not geography. It is not their land route, but you know that little strip called Kurdishstan, is what they are after. The Kurds, if you look at them are not Arab, they are a Greek tribe from Alexander's day. Now don't fight me on this. It is in the history books.
So, you are a vet, look at the map. Who would love that little strip there between Turkey and Iraq? It is easy enough. You have to think global historical power, not this post WW2, UN map. The natural features are still there. The plains of old Babylon's Persia circa Darius II, between the rivers are still there. The Fulda Gap thru Poland. Nothing has changed. It is still power, not law.
Russia has no warm water ports, but, Afghanistan does, right..... So, ice free Navy bases in the Med are very important. The Black Sea is bottled by the Dardanelles. Russia has no war time access to ice free ports. Somewhat important, Very Important, or Undecided?
So, Iran bases it's Med sea power, where?
And there isn't really a country in the way anymore, is there? Iraq? We pulled out? Sadam was guarding those North Plains with Turkey. He was very cruel to the Kurds, when the fought back. But, how do you think Iran will take Iraq to get the land route to their Sea Bases in Syria?
The won't take the mountain route, another natural barrier. Right? No. The will wink with Turkey around and thru the Kurds. So, there is only one country between Iran and Syria to completely the Med Sea access with direct land route. HINT: Iran aready supplies it's Navy by overfly this country, uncontested. Lot of money down the drain.
It is the country we just abandoned. Iraq. See? Without a strong block in Iraq, Iran can road supply their Navy if they want to. Remember how Turkey blocked our access in the Iraq War. That shows how easy it is to march tanks thru there. Don't think about the last War, Sailor. I thank you for your service to the Republic.
Think about this War. The one with Iran.