Meanwhile, there are some traditional battleground states - like Ohio and Iowa - that are becoming older, whiter and less educated. That's turning them from true battlegrounds into more reliable red states.

As those states and others in the South and West become more diverse and educated, they will become harder for the Republican Party - in its current form - to win.

Jeb Bush was supposed to be the establishment candidate, but he didn't catch on. And the extraordinary thing about this Republican primary is that the establishment, moderate wing of the party has sidelined itself. They're not coalescing around one candidate as they have in the past.

For Democrats, anything less than 15 net pickups will be a disappointing outcome [in presidency race].

Michael Rubio said Trump's plan was impulsive and not well thought out. The other thing that's really annoying Republicans is that this was supposed to be their great week. The president gave a speech on terrorism that was not well received. They were working hard to tie Hillary Clinton to the president. Then along comes Donald Trump, and the story changes dramatically.

Republican candidates have won whites with college degrees in every presidential election since polling began.

[Hillary] Clinton has also struggled with key groups of voters.