As I don't speak/read Dutch, the most detailed article I found about this is in Der Spiegel. In summary (from there), the Dutch law commission found
- that the 2003 invasion of Iraq was illegal
- that the political support that the Dutch government gave to the aforementioned was "to some extent disingenuous" (due to them repeating US' WMD claims)
But the catch is that the Dutch contingent that went into Iraq in 2003 followed a similar pattern as the Italian and Spanish ones, meaning it only went in a few months after the US had deposed Saddam. (To reinforce that point, the Dutch force was called SFIR -- Stabilization Force Iraq.) So, given these additional circumstances, what did the Dutch law commission find about their own military (SFIR) participation. Was that illegal or not?