The classic question is why the repetition of Tzedek?
I don't recall who said this answer first....
Look at this way:
See the first Tzedek as an adjective
Thus translate it as:
"Just Justice shall you pursue"
It's not enough to seek Just Ends
They must be pursued via Just Means
L'havdil, the US Constitution echoes this
"No one may be deprived of Life, Liberty, or Property without due process of Law."
Taking the Law into one's own hands is not acceptable. (wth rare exception)
Shooting George Wallace or Yitzchak Rabin is not an OK approach.