US Election: Clinton says she will focus on issues, not Trump

US Democratic candidate Hillary Clinton has said she no longer cares what her Republican rival Donald Trump might say and will focus on issues instead.

"I debated him for four and a half hours," she said, recalling their acrimonious exchanges. "I don't even think about responding to him anymore."

She was speaking to reporters aboard her campaign plane.

Mr Trump used a rally in Gettysburg to promise curbs on lobbying and new trade and climate change negotiations.

With just 16 days until the election, much of the recent focus has been on controversies linked to his campaign.

More polls on Sunday suggested the tycoon lags behind Mrs Clinton in key battleground states.

Her campaign has predicted this is going to be "the biggest election in American history".

Campaign manager Robbie Mook told Fox News Sunday: "More people are going to turn out than ever before."

The polls may be wrong in Arizona but if they are correct, it may be the start of a Democratic trend that doesn't just put the state in play in a Clinton 2016 rout scenario, it makes Arizona a legitimate swing state in coming elections.

"The demographics in the state are continuing to change," says Arizona State University political science professor Richard Herrera. "If there is another increase in Latino voters, which there almost certainly will be, followed with an increase in party registrants, this could become a real battleground in future elections."

For Democrats, that's a dream scenario, giving them new and plentiful paths to electoral success.

For Republicans, it could mean the start of a long-term political nightmare.