Rumbling across the Rust Belt in a red, white and blue luxury bus, Vice President Cheney began his remarks at a series of Fourth of July rallies with a recitation of President Bush's record, then turned to bashing Sen. John F. Kerry as a slippery liberal.

"This is the good part of the speech," Cheney told a sweltering, blue-collar crowd Saturday in Parma, Ohio. At two stops in a row, Cheney accused Kerry of "amnesia" about his own record and described him as being "on the left, out of the mainstream, and out of touch with the conservative values of the heartland."

Cheney's relish for the attack makes him an effective tool for the campaign, allowing Bush's team to level tough charges that will get wide attention, while allowing the president to keep his distance. But Cheney is a blunt instrument in an age when politics is delicately choreographed. His willingness to speak his mind has continued to provoke controversies, strategists on both sides said.

At a time when Republicans are unified on nearly every other question, a number of well-known party members continue to talk privately about the possibility that Cheney will be replaced before the party's convention at the end of August. White House officials said there was no possibility that would occur. But one GOP official, exasperated with Cheney's continued talk about Iraq's supposed arsenal of weapons of mass destruction, compared him to the Japanese guerrillas who filtered out of the jungle in the 1950s, not realizing World War II was over.

The three-state bus trip, Cheney's first major swing of this campaign, was a crucial chance for him to prove to Republicans that he is still an asset to the ticket, as he was in 2000 by lending experience and gravitas when Bush was a rookie on the national stage, and not the liability that Democrats and some pollsters say he has become because of diminished appeal and credibility.

White House officials said the trip was a signal that the question has been settled: Cheney is staying, and will be deployed not just to conservative strongholds, but to swing states as well -- to do what he does best, which is attack the opposition and talk tough about protecting the United States.

In the calculations that go with a presidential campaign, Bush's advisers have concluded that although Cheney's most important contribution is revving up conservative voters, he will not hurt Bush's effort to appeal to independents and could even help in reaching out to swing voters.

"Dick Cheney was made for this campaign," Bush-Cheney campaign manager Ken Mehlman said, saying the vice president has longtime credibility on the central issues of national security and the economy.

A White House aide said that independent voters in places such as Pennsylvania want "strong, serious, experienced people defending them from terrorist attacks around the world, and they know he is that."

"Suburban moms like that strong tough guy protecting their kids," the aide said. "The blue-collar worker who hears Dick Cheney give a straightforward, between-the-eyes answer says, 'Damn right,' whether it's [Cheney] sticking it to the enemy or it's him being honest about some foreign leaders and some international institutions not doing as much as they could."

A Cheney adviser who insisted on anonymity said the vice president's appeal to conservatives, along with the fact he has no intention of seeking the presidency in four years, has given him permanent job security with Bush.

"He is extraordinarily important to the base, and the base is extraordinarily important in this election," the adviser said. A White House official said Bush's aides are always worried about the right wing because of President George H.W. Bush's experience, and that with conservatives, replacing Cheney would be "worse than raising taxes" -- the mistake made by the elder Bush.

Republican frustration with Cheney increased recently when a White House effort to raise his profile, after years of near-invisibility, produced mixed results. Most notably, he used a four-letter word to insult Sen. Patrick J. Leahy (D-Vt.) on the Senate floor on June 22. Cheney felt the senator had attacked his integrity. The vice president later expressed no regret, and told an interviewer that he "felt better afterwards."

Tony Perkins, president of the Family Research Council, a conservative group that is a crucial White House ally, said in a telephone interview that Cheney's outburst contributed to the coarsening of politics. Perkins said that the decision not to apologize is "telling of who he is as an individual -- if he's fine with it, that's who he is."

About the same time, Cheney drew the president back into broad claims about links between Iraq and the al Qaeda terrorist network, the day before the Sept. 11 commission announced its conclusion that there was no "collaborative relationship" between Saddam Hussein and al Qaeda.

Some Republican officials also said they are concerned about the renewed scrutiny Cheney will receive when Kerry names his running mate. Andrew Kohut, director of the Pew Research Center for the People and the Press, said the risk of Cheney's campaign appearances in swing states is that he "will raise the profile of the things that people don't like about Bush," including secrecy and the administration's case for invading Iraq.

A CBS News/New York Times poll last month put Cheney's favorable rating at 22 percent, compared with 39 percent for Bush. Cheney's unfavorable rating was 31 percent -- nearly tripled from 11 percent early in 2002. Bush had a 79 percent approval rating among Republicans; Cheney's was 48 percent.

Democrats contend that Cheney helps do their work for them, by symbolizing their charges that the White House is too secretive and more concerned about energy companies than average workers.

Cheney's defense of his ties to Halliburton Co., the Texas-based energy firm that he headed and that is the biggest beneficiary of U.S.-funded contracts in Iraq, gets a close-up in Michael Moore's film, "Fahrenheit 9/11." Comedian Jon Stewart has made repeated use of a clip of Cheney denying to an interviewer last month that he had made a statement connecting Iraq to the attacks on the World Trade Center and Pentagon, followed by a clip of Cheney making the statement on NBC's "Meet the Press" two months after the attacks.

Kerry pollster Mark Mellman called Cheney "a ball and chain that Bush is carrying around." Tad Devine, a Kerry strategist, said Cheney "embodies a lot of the negative traits" about Bush, including that he is "stubborn and ideological."

Cheney's main political function has been as minister to the right wing, but the trip aboard the campaign's armored "Yes, America Can'' bus took him to Ohio, West Virginia and Pennsylvania -- all toss-up states. Suburban voters are critical in Pennsylvania, which some Bush aides say is the big state they have the best chance of adding this time to their tally from 2000. Bush on Friday will make his 30th visit to Pennsylvania, his fourth most-visited state after Texas, Maryland and Virginia.

Cheney, over shouts of "U.S.A.!" and "Four more years," told an indoor Independence Day rally in Pittsburgh, at the Soldiers and Sailors National Military Museum and Memorial: "We'll see you again many times in this campaign."

Cheney -- who appeared at every stop with his wife, Lynne, and their 10-year-old granddaughter, Kate -- also made remarks from the back of a classic convertible in Lisbon, Ohio; toured the Pro Football Hall of Fame in Canton, Ohio; and threw out the first pitch for the minor-league Altoona Curve team.

Under a gazebo in the town square of Ligonier, Pa., Cheney joked, "We do have an opponent out there." Stroking the back of his head, he said, "I'm trying to remember now," until the crowd shouted Kerry's name.

Mary Matalin, who is Cheney's former counselor and plans to travel with him on some key campaign trips, vowed that he will become "the king of swing," referring to plans for Cheney to campaign in battleground states.

"Talking about image makeovers misunderstands this campaign," Matalin said. "This campaign is about substance, and that's what he does best."

Frank Newport, editor in chief of the Gallup Poll, said the use of the obscenity may have hurt Cheney with the white Protestant voters that Bush's aides consider their most crucial voting bloc. But a Cheney aide said the rebuke was the most popular statement the vice president had made in months, aside from his eulogy of former president Ronald Reagan at the Capitol. The aide said Cheney has received hundreds of e-mails and calls complimenting him.

"It was a give-'em-hell-Harry moment," the aide said. "It's been huge."

Joined by wife Lynne in Pittsburgh, Vice President Cheney told supporters in a key state, "We'll see you again many times this campaign."