The constitution requires that certain appointments made by the president be approved by congress. That is part of the separation of powers, the checks and balances built into the constitution. There is a provision to make appointments when congress is in recess... which allows the president to appoint people to boards for a two yr period without congressional approval when congress is in recess. That keeps things from drawing to a halt when congress is away.
President Obama, supposedly himself a "constitutional scholar"... could not get some people he wanted to appoint to the National Labor Relations Board approved by congress. So rather than accept the checks provided in the constitution, he said he was appointing them as "recess appointments". Problem is... congress was not in recess.
In response, congress sued saying the appointments were invalid.
Wednesday the courts ruled that the faux "recess appointments" were in fact unconstitutional and were invalid from the point at which they were made. That likely vacates all decisions made by that board since that point.
This is what happens when a president decides he's a fucking king. Obama tries to shred the constitution on a regular basis. This time he got caught. The white house plans to appeal. Basically their argument is pretty much "but gee, congress wasn't getting anything done".
We have a system of checks and balances that is intended to make our executive, judicial and legislative branches CO-EQUAL branches. The president isnt a monarch. This one seems to forget that.
Court: Obama appointments to labor panel are unconstitutional | Fox News