Mishpatim means civil and criminal laws which are self-understood. As Rashi comments. "laws recorded in the Torah that, if thay would have not been given, it would have been appropriate to instiute them in any case" (commentary to Bamidbar 18:4).
Furthermore, these laws are self-evident not only to the Jewish pepole, but also to the nations of the world, such that it is feasible that a secular law is identical to a Jewish Law.
For this reason, it is stated at the begining of the Parsha, "And these are the Laws...," to which Rashi comments, "these are also from Sinai," maening that even these laws which are rationally dictated by the human mind must be observed (not because of their intellectual credibility but) because thay are God's commands. It is onky tht God wanted these commands to be understood by man.
For this reson, these laws are placed, "before them" - "and not before the nations... even where thier decision would conicide" (Rashi), since their laws are basde on human reason, and it neccessary to observe our precepect as Divine decrees.
At a deeper level, it could be argued that tha concept of mishpatim from Sinai implies that tha very essence of rationality itself was also implanted at Sinai. if it were not for inteligence would not have been able to fathom them (just like the other super-rational commandments).
The rational nature of the laws is a result of God`s Will (which is intrinsically unfathomable) being invested in His Torah. Since the Torah is the "record and register" which was used to create the world, these laws became compatible with the fabric of the world, and commensurate with human understanding. Consequently, the human mind (including that of non-Jwes) naturally tends towards the wisdom of God, which is precisely was communicated as Sinai.
(Based on Sichas Shabbos Mishpatim 5752)