HENDERSON, Nevada (AP) — The U.S. presidential race was relatively quiet Monday, with the candidates studying for their first debate on Wednesday and the now-trailing Republican Mitt Romney hoping to change the trajectory of his campaign.

Adding to the performance pressure was the growing momentum in early voting, with the most important of the battleground states that will decide the Nov. 6 election, Ohio, starting to take ballots Tuesday.

President Barack Obama was huddling with top advisers at a desert resort in Nevada. Romney was practicing in Massachusetts before heading to Colorado, the site of the first debate and another of the handful of states that will determine the election.

Polls show Romney trailing Obama in many of those nine battleground states, which do not reliably vote Democrat or Republican and have been deluged by campaign ads and visits.

The three debates this month give Romney one of his best, and last, opportunities to stop Obama’s rise in the polls and convince the public to support his vision for pulling the country out of its economic weakness.

The first debate is focused on domestic issues like the economy, which remains voters’ top concern.

“What I’m most concerned about is having a serious discussion about what we need to do to keep the country growing and restore security to hardworking Americans,” Obama said during a rally in Las Vegas Sunday night. “That is what people are going to be listening for. That’s the debate you deserve.”

Republicans were keeping up the pressure on Obama on international issues, namely his administration’s handling of the attack on a U.S. consulate in Libya that led to the death of the U.S. ambassador and three others.

The Obama administration has called it a terrorist attack. It came amid violent protests in the Muslim world over an amateur anti-Islam film made in the U.S.

Romney, in an opinion piece in The Wall Street Journal, repeated his criticism of Obama for having called the attack and other unrest in the Middle East “bumps in the road.”

“Our country seems to be at the mercy of events rather than shaping them,” Romney wrote. “We’re not moving them in a direction that protects our people or our allies.”

Both candidates were spending the days leading up to the debate in battleground states, with Romney in Colorado and Obama in Nevada.

Obama told a rally Sunday night that while he was “just OK” at debating, his opponent was “a good debater.”

Romney’s running mate, Paul Ryan, on Sunday shot down the idea that Romney needed to have a breakthrough performance Wednesday, saying he didn’t think one event would make or break the campaign.

Romney’s team has made no secret of the fact that the former Massachusetts governor has been practicing intensely for several weeks.

Obama aides have kept quiet about how and when the president is practicing.

___

Associated Press writer Kasie Hunt in Boston contributed to this report.

___