From VP choice in 2012 to:
PPP National Poll, March 14.
Huckabee 18%
Bush 15%
Christie 14%
Paul 14%
Cruz 11%
Rubio 6%
Ryan 5%Walker 5%
Jindal 4%
My theory:
1. He didn't really have a clear base of support. He was just.... "acceptable" to almost all GOP factions.
2. The Bipartisan Budget Act.
http://en.wikipedia.org/wiki/Bipartisan_Budget_Act_of_2013 Worked with Dem Senator Patty Murray to create a bipartisan solution. RINO!
3. As a House member, he became considered as a candidate less often than Governors and Senators, who increased their standings in the 2016 polls. Example: Walker, who he is now tied with in this poll.