Trump at 28% on the strength mostly of the immigration issue. There are other issues, any of which could give him another significant boost once discussed more thoroughly.
1. Bad trade deals that have moved US plants and jobs overseas, and the outsourcing of jobs, H1-Bs, etc. Upcoming trade deals.
2. Trump opposes Common Core.
3. The sluggish economy in general.
4. Out-of-control spending and the $18.5 trillion debt.
5. His belief that a growing economy and job creation can secure SS and Medicare for the future, and help solve most other problems. Relates to 1, 3, and 4, and illegal immigration and probably excessive legal immigration.
Several only slightly discussed issues, any of which can give Trump another good boost compared to the position of other candidates.
6) Ridicule Vallerie Jarrett and Huma Abedin - Weiner as surrogates for Obama and Hillary respectively.