The President has failed to do most of the important of the things he promised as a candidate, and has shown continued disdain for the laws of the US, especially those that limit the power of the Executive branch.
The numerous scandals plaguing his administration, which are shameful to say the least, belittle his important Office and cripple his ability to effectively govern. They also have brought about a lack of confidence in his resolve and leadership. The Nation needs both for its leader.
(And I did vote for him.)