Republican John McCain blasted rival Barack Obama for not having been to Iraq since 2006, taking the occasion of the US Memorial Day holiday to portray the first-term Democratic senator as naive on foreign policy and not as qualified to lead the military as president. McCain, a Navy veteran and Vietnam prisoner of war, believes that US troops should stay in Iraq as long as it takes to win, and has frequently argued that he is the most qualified candidate to be a wartime commander in chief. Obama has favored a quick withdrawal, a stance McCain slammed in a speech before veterans in New Mexico on Monday. The two candidates recently have largely ignored Hillary Rodham Clinton, Obama's long-shot rival, who was continuing to campaign Monday in Puerto Rico. The US Caribbean territory's primary on June 1 is one of just three left as the intense months-long battle for the Democratic presidential nomination winds down and Obama looks to be the inevitable nominee. Obama and McCain both were on a campaign swing through three Western states that could prove to be pivotal battlegrounds in the November general election. Both candidates spent Memorial Day in New Mexico. Obama was heading Tuesday to Nevada to talk about the housing crisis at campaign events in the Las Vegas area and later in the week he was heading to Colorado. McCain was scheduled to speak in Denver on Tuesday and then hold a town hall meeting the following day in Reno, Nevada. Obama was signaling, even before the Democratic primary campaign formally wraps up, that he intends to fight this fall for the three Western states that narrowly went Republican four years ago. "We're going to fight as hard as we can in these states. We want to send the message now that we're going to go after them and I expect to win them," the Illinois senator said Monday. US President George W. Bush won New Mexico over John Kerry four years ago by the tiniest of margins - 49.84 percent to 49.05. His margins were not a whole lot bigger in Nevada (50.5 to 47.9) and Colorado (51.7 to 47). McCain said Monday that Obama "has no experience, no knowledge or background" on Western issues. "I believe as a Western senator I understand the issues, the challenges of the future for these ... states, whether it be land, water, Native American issues, preservation, environmental issues," McCain said in an interview with the AP. Obama said he needs to introduce himself to all Western voters, not just Hispanics. Issues like improving the economy, ending the Iraq war and providing universal health care will appeal to everyone, he said. "I'm absolutely confident that we're going to do very well ... here because people out west are independent-minded and are going to look at whether or not over the last eight years the country is better off under Republican rule. I think they're going to conclude they're not and they want fundamental change, something that I'm offering and John McCain is not," he said. The Iraq war, which polls show most Americans oppose, has been overshadowed by economic concerns on the campaign trail, but could be a defining issue in the November presidential election. In an interview with The Associated Press on Monday, McCain noted that Obama's last trip to Iraq came before the military buildup that is credited with curbing violence, and said the Democrat's call for withdrawal is "inexcusable." McCain has been to Iraq eight times, most recently in March. "He really has no experience or knowledge or judgment about the issue of Iraq and he has wanted to surrender for a long time," the Arizona senator said. "If there was any other issue before the American people, and you hadn't had anything to do with it in a couple of years, I think the American people would judge that very harshly." Obama spokesman Bill Burton declined to respond directly to McCain. "Senator Obama thinks Memorial Day is a day to honor our nation's veterans, not a day for political posturing," Burton said. In his speech to veterans, McCain distanced himself from the Bush administration's handling of Iraq, acknowledging that Americans are unhappy with the war, but arguing that US commanders in Iraq need more time. "As we all know, the American people have grown sick and tired of the war in Iraq," the presumptive Republican nominee said. "I, too, have been made sick at heart by the many mistakes made by civilian and military commanders and the terrible price we have paid for them." But, if the US were to pull out now, "our defeat would be catastrophic, not just for Iraq, but for us." McCain also defended his opposition to a Senate plan for increasing military veterans' college benefits, saying his was the right position rather than the politically expedient one, and suggesting Obama was on the wrong side of the measure sponsored by Democratic Sen. Jim Webb, himself a Vietnam veteran. Obama spent much of last week criticizing McCain over the college aid bill, part of a strategy to link the conservative Republican - who favors staying the course in Iraq - to the deeply unpopular Bush administration. The Democratic-controlled Senate approved the bill, which would substantially increase educational benefits for service members returning from Iraq and Afghanistan. Lawmakers blocked a more limited version that McCain supported. McCain opposed the Webb measure because it would give the same benefit to everyone regardless of how many times he or she has enlisted. Obama on Monday acknowledged that unlike McCain he has no military experience, but said he is committed to strengthening the military and improving veterans' services. "As president of the United States, I will not let you down," he promised a group of veterans in New Mexico, a battleground state in the general election. Obama said Bush is asking the troops to do too much with too little, such as interacting with civilians without the necessary translators and handling nation-building tasks that could be done by the State Department and other agencies. Clinton, meanwhile, was in Puerto Rico, where she hopes for a big primary victory June 1. She met with a family whose soldier son is awaiting redeployment to Iraq, saying she would end the war so "you will not have to worry about him going back to Iraq." Clinton is trailing Obama and has almost no chances of getting the Democratic nomination. Some prominent Democrats have been calling for her to step down, fearing that a long nomination battle might ruin the party's chances in the November general election. The former first lady spoke of her determination to stay in the race despite trailing Obama, who has 1,977 delegates, just 49 delegates short of the 2,026 needed to clinch the nomination. Clinton has 1,779. A total of 55 delegates are at stake in the Puerto Rico primary. Puerto Rico does not vote in the general election in November. The last primaries on the Democratic calendar will be held in Montana, with 16 delegates at stake, and South Dakota, with 15 delegates, on June 3.