John McCain is taking no vacation from pummeling his Democratic opponent, accusing Barack Obama on Saturday of being unfit for command just as the Illinois senator began his weeklong holiday in Hawaii.

The Arizona senator used his weekly radio address and a speech before the Disabled American Veterans in Las Vegas to drive home that point.

He told the veterans' organization that Obama is shifting positions on Iraq and criticized Obama for saying in July that he would have still opposed the troop surge if he could do it again.

"Behind all of these claims and positions by Senator Obama lies the ambition to be president," McCain said. "What's missing is the judgment to be commander in chief."

Speaking Friday to reporters aboard his campaign plane from Arkansas to Las Vegas, the Arizona senator said he planned to campaign as usual next week while Obama is on vacation and many voters are watching the Olympic Games.

The presumptive GOP presidential nominee is trying hard to catch up in the polls. A week ago, McCain had closed the race to a tie in the Gallup daily tracking poll, after Obama had opened up a 9-point lead on the heels of his high-profile trip abroad.

But on Saturday the Gallup poll showed Obama leading by 5 points, 47-to-42 percent.

Long known for his freewheeling campaign style and extemporaneous exchanges with reporters, McCain has gotten more buttoned-down and less available to the press in recent weeks as his campaign has ramped up its attacks on Obama.

McCain told reporters he adopted the new style to bring more discipline to his campaign message, but he said he hoped to be more available to the media in the future.

"My inclinations are always that," he said. "I know we've been out of contact, we'll get in more contact. It's been a busy couple weeks."

His campaign released a flurry of ads on Friday portraying Obama as an empty celebrity, and McCain hit that theme again in his weekly radio address, in which he said he anticipated an impressive speech from Obama at the Democratic National Convention.

"Even the most stirring speeches are easily forgotten when they're short on content. Taking in my opponent's performances is a little like watching a big summer blockbuster and, an hour in, realizing that all the best scenes were in the trailer you saw last fall," McCain said.

"In the way of running mates, Senator Obama should consider someone with a knack for brevity and directness, to balance the ticket," he said.

Even as he enjoys some downtime, Obama has still found ways to hit back.

For the first time Saturday, he made a radio address of his own. In it, he accused McCain of embracing Bush administration policies that he said have shortchanged Americans by favoring an extended war in Iraq at the expense of fixing the nation's infrastructure.

The Illinois Democrat pointed to a recent Government Accountability Office report that found the Iraqi government could end the year with a budget surplus of as much as $79 billion while at the same time spending only a fraction on reconstruction costs that are largely borne by the United States. McCain will only continue Bush war policies with an "open-ended commitment" that has been unsuccessful, Obama said.

The campaign also unveiled a new TV ad in Nevada accusing McCain of being a "leading proponent of storing nuclear waste in the state of Nevada" at the Yucca Mountain site.

In response, McCain's campaign needled him for the Hawaii holiday.

"Apparently Barack Obama is also taking a vacation from the facts, ignoring his own votes in support of the Yucca Mountain project," spokesman Tucker Bounds said.

The Associated Press contributed to this report.