My dear brother, this is a real misconception people have.
1. Afghanistan and Vietnam were occupations where the United States had boots on the ground and were actively engaged in Nation building experiments.
2. the type of warfare between Iran and US/Israel etc is Asymmetric, including economic blockades and pressure through regional networks/allies from either side. In Afghanistan and Vietnam the US were engaged in sustained deployments of ground troops seeking to gain control territory and defeat local insurgencies.
In Iran the U.S. relies heavily on aerial bombardment, cyber warfare, sanctions and diplomatic pressure.
3. In Afghanistan the US were fighting the Taliban that were a highly decentralized non-state insurgency that relied on guerilla warfare, Iran conversely is a country with sophisticated military and a vast arsenal of ballistic missiles, drones and conventional weapons presenting a different strategic challenge.
4. Whilst in Vietnam the US occupied that land for over 10 years to install and protect allied governments, in the case of Iran, the US objectives have been containment, pressure and neutralizing what they deem as threats.
---
Like I said, apples and oranges.
Some light reading for you:
‘Today, we tell the despotic regime in Saudi Arabia that we will not be part of their military adventurism’, said Senator Bernie Sanders on 13 December 2018, as the Senate voted to end U.S military support for Saudi Arabia’s conflict in Yemen. Despite bipartisan support for this resolution...
blogs.lse.ac.uk