PORTSMOUTH, N.H. — “I have not yet begun to fight.”

That was the message of Senator McCain’s official announcement of his candidacy for the presidency. Mr. McCain spoke here yesterday in front of Portsmouth Harbor, the locale where Revolutionary War naval hero John Paul Jones, who uttered those famous words, took possession of the Ranger, the first warship to sail under the American flag.

“Our challenges are an opportunity to write another chapter of American greatness,” Mr. McCain said. “We must seize it, and those of us privileged to lead America must remember the principles that made us great, have the faith to stand by them … and the courage to keep our promise to put the nation’s interest before our own.”

While remaining firm on his support of the American military effort in Iraq, Mr. McCain notably used rhetoric to reach out to voters unaligned with either political party and distanced himself from the Bush Administration. Independents can vote in the New Hampshire primary and were an important component of Mr. McCain’s primary victory in New Hampshire in 2000.

“This election should be about big things, not small ones. Ours are not red state or blue state problems. They are national and global,” Mr. McCain said in language strikingly similar to Senator Obama’s address to the Democratic National Convention in 2004. “Half measures and small minded politics are inadequate to the present occasion.”

Mr. McCain also spoke of “mistakes” relating to the war in Iraq. “America should never undertake a war unless we are prepared to do everything necessary to succeed, unless we have a realistic and comprehensive plan for success, and unless all relevant agencies of government are committed to that success.”

Addressing a crowd in the cold drizzle of Manchester, Mr. McCain was interrupted by anti-war protesters who shouted, “No more blood for oil!” In response, Mr McCain invoked the New Hampshire state motto: “This is what free speech is all about. Live Free or die.”

Speaking to reporters after his speech, Mr. McCain responded to a question asking him to compare the wars in Vietnam and Iraq. “We all know the American people thanks to the Tet Offensive would not support it,” Mr. McCain said of Vietnam. He added that even with success “on the battlefield,” they would not back the military effort.

During his speech, Mr. McCain contrasted himself subtly to President Bush, whose election in 2000 was thrust into the U.S. Supreme Court and won somewhat narrowly in 2004, Mr. McCain said “I can’t just win this election by a few votes in a few counties in a few states.” Instead, he said needed “a mandate big enough to convince Congress that Americans want this election to be different.”

The Arizona senator returned to themes that served him well in New Hampshire in 2000. He traveled across the state in a blue bus dubbed “the Straight Talk Express.” He inveighed against the “wasteful spending” of government money. But this time, he touted his experience as well. “I am not the youngest candidate. But I am the most experienced,” he said, citing his understanding of the military, Congress, and foreign affairs.

Mr. McCain drew a largely respectful, interested crowd. A few critics were present as well. Burton Cohen, who had served as a state senator as a Democrat, held a sign reading “2000 – 2008, Different McCain, Different New Hampshire.” Mr. Cohen explained his presence by saying he wanted to bring the troops home.

The presence of the critic drew the ire of Peter Weeks, a former mayor of Portsmouth and a supporter of Mr. McCain. “He won the state in 2000. He’s going to win the state in 2008,” Mr. Weeks said. “The Democrats are afraid of him.”

Given Mr. McCain’s candidacy in 2000, he commands an active political organization in the state. The vice chairman of his campaign in New Hampshire, Steve Duprey of Concord, said the campaign drew volunteers from veterans groups, hunters, and people with a background in law enforcement. Mr. Duprey, the former chairman of the Republican Party in New Hampshire, said Mr. McCain had no trouble building crowds, unlike his prior candidacy when he “had to offer free ice cream to get people here.”

After the announcement, many supporters of Mr. McCain’s went to nearby Geno’s for lunch. On display at Geno’s, a sandwich and chowder shop tucked next to the water, were seven photographs, some of them autographed, of President Bush. Also hanging were photos of President Bush’s mother, Barbara, standing with Mrs. Marconi, the proprietor of Geno’s. Hustling to fill chowder orders for supporters of Mr. McCain, Mrs. Marconi was asked whether she backed Mr. McCain. She said she supported Governor Romney. Mr. Romney is set to appear at Geno’s this morning.