John McCain made a fresh attempt Tuesday to put miles between himself and President Bush, releasing an ad that claims the country is worse off than it was four years ago.

Seeking to counter charges that he's offering a third term for Bush, the Arizona senator emphasized his independent streak and referenced the conflicts he's had with the Republican Party during his tenure in the Senate.

"Washington's broken. John McCain knows it," the announcer in the ad says. "We're worse off than we were four years ago.

"Only McCain has taken on big tobacco, drug companies, fought corruption in both parties. He'll reform Wall Street, battle 'Big Oil,' make America prosper again. He's the original maverick."

The brief ad is being released as both McCain and Barack Obama battle over energy policy, each fighting to be seen as the candidate with the most innovative and effective proposals for ending dependence on foreign oil and driving down fuel prices.

The Gallup daily tracking poll also showed Obama opening up a 47-to-43-point lead over McCain, after the two were tied over the weekend.

McCain was set to tour a nuclear power plant in Michigan Tuesday, the first such visit in recent history by a presidential candidate.

The Enrico Fermi Nuclear Plant outside Detroit, named for the first physicist to split the atom, is home to both an operating power plant and another reactor that had a partial meltdown in the 1960s. It was decommissioned in 1972, while its successor continues to operate.

McCain is placing great stock in modern-day nuclear technology by calling for the construction of 45 nuclear power plants by 2030. The Republican argues that its carbon-free power generation is necessary to reduce the country's reliance on oil imports.

Meanwhile, the Obama campaign rejected McCain's claims to be the scourge of Washington insiders.

The campaign released a counter-ad late Tuesday noting that McCain supports the Bush tax cuts and "oil company giveaways."

"The original maverick? Or just more of the same?" the narrator says.

"Senator McCain wants Americans to forget that during the Republican primary, he said that Americans were better off than we were eight years ago, and that he thinks we've made ‘great progress economically.' He wants us to forget that he's fully embraced the Bush policies he once opposed," spokesman Bill Burton said in a statement.

"The truth is, being a maverick isn't practicing the same kind of politics we have seen from Washington for decades."

At an energy-themed town hall meeting in Youngstown, Ohio, Obama referenced the vice president, saying, "McCain has taken a page out of the Cheney playbook."

With polls showing concern over gas prices a prime concern of Americans, Obama has been depicting energy as the nation's most pressing national security and economic issue. In that effort, he criticizes McCain as more concerned about oil company profits and drilling than an overall energy strategy.

"Senator McCain not only wants oil companies to keep every dime of that money that they've been making, he wants to give them more," he said. "The oil companies have placed their bets on Senator McCain, and if he wins, they're going to continue to cash in while ordinary families and our economy suffer and our future is put in jeopardy."

However, Obama voted for a 2005 energy bill backed by Bush that included billions in subsidies for oil and natural gas production, a measure for which Vice President Dick Cheney played a major role. McCain opposed the bill, saying at the time that it included billions in unnecessary tax breaks for the oil industry.

The Obama campaign has said the Illinois senator supported the legislation because it included huge investments in renewable energy.

Democrats long have characterized the 2005 energy bill as being written by Cheney. In January, Democratic primary rival Hillary Rodham Clinton criticized Obama's support for the bill, calling the measure the "Dick Cheney lobbyist energy bill."

In his own energy plan, Obama has proposed a $1,000-per family energy rebate to be paid for by a tax on excessive energy-company profits. He called for ending U.S. reliance on oil from the Middle East and Venezuela over the next 10 years, a project he said would cost the U.S. $150 billion.

Obama has also proposed borrowing oil from the strategic petroleum reserve, a conditional and limited resumption of offshore drilling, and a new emphasis on alternative energy sources and hybrid vehicles.

It was Obama's second day on a tour featuring a stepped-up emphasis on energy and harsher criticism of McCain.

Increasingly, with his appearances this week and with a new ad, Obama has been seeking to tie McCain to the oil and gas industry, even though McCain has no direct ties to the industry, unlike Bush and Cheney, who both worked in the industry before their election.

A new Obama ad says "Big Oil" filled McCain's campaign with $2 million in contributions and that he "wants to give them another $4 billion in tax breaks."

However, that consists mainly of potential revenue from a McCain proposal to lower corporate taxes on all American businesses.

The McCain campaign has also pointed out that the ad doesn't mention Obama has taken some $400,000 from oil company executives.

Obama has had trouble connecting with white working-class voters, who are a major factor in Ohio. Hillary Clinton won the state in its Democratic primary earlier this year. Gov. Ted Strickland, who had been a Clinton supporter, gave a rousing endorsement of Obama, calling him "bright, young, energized and compassionate."

FOX News' Bonney Kapp and The Associated Press contributed to this report.