On Saturday, the United States and Iran held direct negotiations for the first time in more than a decade. The talks ended without a deal, as the US and Iranian positions remain far apart.

While it is unclear what will happen next, the past month and a half of fighting has cast light on important lessons to be learned not just about this conflict but also the nature of modern warfare. These may turn into key considerations for decision-makers in Washington as they determine what to do next.

Scale and geography matter

Iran operates on a scale that immediately complicates any direct confrontation. With a landmass of approximately 1.64 million sq km (more than 633,200sq miles) and a population exceeding 90 million, the country dwarfs the environments in which recent major wars have taken place.

By comparison, Iraq — invaded by a US-led coalition in 2003 — has roughly one quarter of Iran’s land area and half its population. Afghanistan and Ukraine, while sizeable, are still significantly smaller in both territory and demographic weight.

This matters because military operations scale nonlinearly. Larger territory does not simply require more troops and weapons; it requires exponentially more logistics, longer supply lines, and expanded intelligence coverage.

If scale complicates the planning of a war, geography compounds it even more.

The US invasion of Iraq benefitted from favourable terrain. Coalition forces advanced rapidly through the relatively flat southern desert and river valleys, enabling a swift push towards Baghdad. Russian forces also benefitted from the relatively even landscape in Ukraine, easily crossing through the steppe in the eastern part of the country.

The problem with flat terrain is that it exposes troops to enemy attacks, as their movements can easily be detected.

Afghanistan presented the opposite challenge: mountainous terrain that limited conventional operations and forced reliance on airpower, special forces, and local allies.

Iran, however, combines the worst of both environments at a much larger........

© Al Jazeera