They are preparing for the first head-to-head televised debate of the US presidential election campaign.
It is being hosted by the University of Denver in the swing state of Colorado.
The evening showdown is expected to draw an audience of up to 60-million people, and will give voters a chance to compare the two side-by-side for the first time.
But Romney has his work cut out. Some polls at the weekend showed the Republican trailing Obama on a broad array of issues.
“These debates are an opportunity for each of us to describe the pathway forward for America that we would choose,” Romney said. “The American people are going to have to make their choices about what type of America they want. So I look forward to these debates. I am delighted that we are going to have three debates. It will be a conversation with the American people that will span almost an entire month.”
Some observers have described Barack Obama as a cool debater, but one who is prone to getting irritable if challenged on specific issues.
“Governor Romney is a good debater. I am just OK,” the president told crowds in Las Vegas. “But what I am most concerned about, is having a serious discussion about what we need to do to keep the country growing and restore security for hard working Americans.”
Recent research seems to show that painting Romney as rich and out-of-touch is paying dividends for the Obama campaign.
When asked who understood the electorate better, potential voters put Obama 20 points ahead.