President Barack Obama (Democrat) recently made a recess appointment, appointing Richard Cordray as director of a consumer protection agency (Consumer Financial Protection Bureau). The problem with this appointment was President Obama made a recess appointment when the Senate was not in recess!
Per the United States Constitutional executive branch appointment must be approved by the Senate. However if the Senate is in recess, the president can make appointments without the Senate’s approval. The problem here is the Senate was in a “pro forma session.” Article I, Section 5, Clause 4, mentions neither House can be adjourned longer than three days without the approval of the other House.