Until he announced his immigration policy last week, Obama had the support of most Hispanic voters - but not the enthusiasm they had shown for him in 2008. That may be changing in part because of the decision not to deport young immigrants whose undocumented parents brought them here as children.

Both the Obama and Romney campaigns said they pulled all their political ads today in observance of the September 11th anniversary. But politics wasn't very far offstage. The Obama campaign sees foreign policy as an advantage this year.

Republican voters are coalescing behind [Donald] Trump, but many Republican elected officials still say they can't support him.

[Donald] Trump's path to victory depends on getting historic levels of support from white voters, and particularly large numbers of white, non-college-educated voters.

There's a lot of anxiety about terrorism among the country at large. There's also a feeling the country has stagnated.

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.

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