Another, more correct way, would be to state North Korea invaded South Korea and the US (and its allies) stepped in to stop them. They did this not to "free North Korea" but to prevent "communism" from overrunning one of its allies.
(They were also so succesful at it they pushed back North Korea almost all the way up to the Chinese border, which got China very nervous, leading to them getting involved as well).
Another, more correct way, would be to state North Korea invaded South Korea and the US (and its allies) stepped in to stop them. They did this not to "free North Korea" but to prevent "communism" from overrunning one of its allies.
(They were also so succesful at it they pushed back North Korea almost all the way up to the Chinese border, which got China very nervous, leading to them getting involved as well).