We have done that, and then allowed for elections, how is this much different? We did it in Afghanistan and then again in Iraq, and both of those countries had to wait waaaaaaay longer than a month for a "free" election.
Not even close to the same.
In Afghanistan:
We were attacked by al Qaeda which was based there and supported by the government (Taliban). No one in Crimea or Ukraine proper attacked Russia.
We are not going to annex Afghanistan. Russia is annexing Crimea.
The Afghanistan government is not by any stretch of the imagination a US puppet government. The Crimean government is a Russian puppet installed by the Russians without an election.
In Iraq:
The world (UN) had imposed sanctions on Iraq that included the authorization that military force be used to enforce a no-fly zone.
For years, Iraq shot at our military aircraft, which is an act of war.
Most countries in the world (the ones that have a robust foreign intelligence system, Britain, Germany, France and others) stated that Iraq had WMD's and would use them (hell even Saddam thought he still had them). Not just the US or Bush as the far left in the US likes to state.
Saddam used WMD's against our troops in the first Gulf War and on his own people.
After multiple attacks by Iraq against coalition military aircraft, the attacks we underwent in 9/11 and the overwhelming intelligence reports from multiple countries that WMD's still existed and that Saddam could sell them to al Qaeda or use them himself, the US with other countries took action.
We left Iraq and have not annexed any territory gained in battle since the Spanish-American War.
Russia is annexing Crimea, and possibly other parts of Ukraine proper.
Russia was not threatened by Crimea or Ukraine with military force, or any force at all.
Russia is isolated in the world, as was evidenced by the latest vote in the UN where the vote condemning the invasion and forced vote was unanimous against Russia with China abstaining and Russia vetoing the resolution.
I could keep going on both of your examples, but I'm getting a headache and by fingers are starting to hurt.