Regime Change

Every so often, the leadership of one country will decide that it doesn't like the leadership of another country. Perhaps there's a longstanding feud between the two leaders, perhaps one wants to take over the other but not look like it, or perhaps the leader of the latter country is bent on causing trouble. Whatever the reason, the first country wants the leadership gone.

Enter Regime Change. Popularized during the run-up to the US invasion of Iraq in 2003, this term can be applied to any number of forms: Invasions, coups, assassinations, fixing elections...you name it, it's probably happened.

Examples:

Film

The Real Life regime change the USA has done in Central America was parodied in Woody Allen's Bananas, when the CIA soldiers already on their way in the airplane had to ask if they were being sent in for or against the current government.
In Star Wars, this is the goal of the Rebel Alliance in their Civil War against the Galactic Empire. After the Battle of Endor, they succeed.

Live Action TV

The Leverage episode "The San Lorenzo Job" had the team attempt to fix the presidential election in the nation of San Lorenzo. They need the current president gone so he can no longer protect a ruthless international criminal who is their real target.

Newspaper Comics

Dogbert has done this more than once in Dilbert.

Web Original

In The Salvation War, the humans do this. To Hell. Not only that, Heaven seems to be next on the list.

Western Animation

In Avatar: The Last Airbender, as part of their effort to end the century-long world war, Avatar Aang and his friends overthrow Fire Lord Ozai and install his son Zuko as leader of the Fire Nation.

Real Life

The Trope Namer was Iraq in 2003. Other instances abound.
Older Than Feudalism: The ancient Romans demanded this as a part of the peace after the Second Punic War.