All of them. Afghanistan as a response to 9/11, Iraq as a regional power flex and entrenchment. The first certainly preserved US status more than letting 9/11 go unanswered, the second to remove a hostile regional power and replace it with a friendlier government.

Now in Iran, the intention was to repeat Venezuela and effect regime change in a hostile country, bolstering America's military status.

Whether these wars have the effect they intend is beside the point; you're asking why they were fought, not whether they resulted in "Mission Accomplished".