Immigration fever puts parties in the hot seat

"Rachel Olivarez-Sellers doesn't bring up immigration anymore as she crisscrosses Colorado trying to reach out to new Hispanic voters. It's just too complicated."  <---  Not really. When an outside population reaches a certain level, it tips the balance of the inside population. The local level at which the balance of the inside population "tips over" is not 50 percent. It's approximately 20 percent.