Uh, yeah you can.
Imagine if we'd done that in Germany in 1945, the Red Army would have swept all through Europe.
Iran is comparable to the "Red Army" and they are sweeping through anyway. A large part of their success is due to the fact that we chose sides in Iraqi politics instead of letting the Sunnis reassert their dominance.
Iran has become the single largest beneficiary of US Tampering in Iraq. It is now virtually a satellite state of Iran. Once again, this is because we empowered the Shia majority by undermining and killing the Sunni minority that was running things when we came and screwed everything up.
Another Iraqi Sunni dictator would have prevented Iran from making so many inroads into Iraq.
We have made about as big a mess of that nation as it was possible to make of it. All our meddling has produced the worst possible outcome.
How could it have turned out any worse than it has?
Well in the end we pretty much did walk away...after spending billions.