CONCORD, N.H. — Dismissing Senator Clinton’s foreign policy as “Bush-Cheney lite,” Senator Obama is serving notice to his main rival that the days of well-mannered debate in the Democratic presidential race are over.

In an appearance here yesterday, Mr. Obama electrified his grassroots supporters by using his toughest language yet against Mrs. Clinton. Mr. Obama stood by his pledge to meet with the presidents of Iran, Venezuela, and Cuba during his first year in office if elected president.

That promise, made in Monday night’s debate, has been the focus of a week of sparring between Mrs. Clinton and Mr. Obama, making the contest feel this week increasingly like a two-person race. In likening Mrs. Clinton to President Bush and Vice President Cheney, Mr. Obama is making an appeal to the party’s left-wing activists, with whom both Messrs. Bush and Cheney are deeply unpopular. The effort mirrors prior attempts to define centrist-minded Democrats as outside the confines of the party, such as last year’s primary challenge to Senator Lieberman of Connecticut.

“It is no longer sufficient to trot out the old formulas, the old tired phrases. If we want fundamental change, then we can’t be afraid to talk to our enemies. I’m not afraid of losing the p.r. war to dictators,” Mr. Obama said to prolonged applause. “I’m happy to look them in the eye and say what needs to be said… I don’t want a continuation of Bush-Cheney. I don’t want Bush-Cheney lite, I want a fundamental change.” Mr. Obama made his remarks at an event at which he received the endorsement of Rep. Paul Hodes, a first-term congressman who defeated Republican Charles Bass in 2006.

Speaking later in the day on a conference call for reporters, Mr. Obama stood by his assertion that Senator Clinton’s refusal to meet to meet with foreign despots during her first year in office on the grounds put her on similar footing with Mr. Bush. “I don’t just believe that. That’s the record,” Mr. Obama said. “The Bush administration’s policy is to say we will not talk to these countries unless they meet various preconditions … You’ll have to ask Senator Clinton what differentiates her position from theirs.” He also said that he would tell the Iranian president “that Israel is our friend and that we will assist in their security and that we don’t find nuclear weapons acceptable.”

Senator Clinton addressed Mr. Obama’s charges in an interview on CNN. “Well, this is getting kind of silly. I’ve been called a lot of things in my life but I’ve never been called George Bush or Dick Cheney certainly. We have to ask what’s ever happened to the politics of hope?” said Mrs. Clinton. “I have been saying consistently for a number of years now, we have to end the Bush era of ignoring problems, ignoring enemies and adversaries. And I have been absolutely clear that we’ve got to return to robust and effective diplomacy. But I don’t want to see the power and prestige of the United States President put at risk by rushing into meetings with the likes of Chavez, and Castro, and Ahmadinejad.”

And, while calling the flap between Mr. Obama and Mrs. Clinton a “false debate” in a statement, Senator Dodd of Connecticut nonetheless warned against a meeting with Mr. Ahmadinejad of Iran: “There are some leaders – like Iran’s Ahmadinejad, who denies the Holocaust ever took place – which cannot and should not be diplomatically rewarded with visits from the American president.”

Mr. Obama’s event here, hastily but efficiently organized, appeared to be an attempt to capitalize on the energy generated by his exchange on foreign policy during the YouTube debate on Monday. While New Hampshire has historically been an independent-minded state, it took a lurch to the left in 2006, when voters elected Mr. Hodes and another Democrat, Carol Shea-Porter, to the House of Representatives. They also elected a Democratic governor, John Lynch. Both branches of the state legislature became Democratic for the first time in more than a century as well. Mr. Obama, during his brief speech, emphasized that changing tide as he made the case that he represented a new beginning.

Area voters were notified Wednesday afternoon of the event in Eagle Square, in the heart of downtown Concord and directly in back of the Illinois senator’s local office. The foci of the Obama campaign appeared to be on providing an effective visual for local television cameras – Messrs. Obama and Hodes, both without suit jackets, standing in front of a crowd of enthusiastic supporters – and collecting personal information from newcomers to the campaign. Building a strong field organization, which can identify and turn out voters, is a key to victory in January’s primary contest. At least 20 young members of Mr. Obama’s team canvassed the crowd with clipboards and cards for attendees at the rally to fill out. While Mr. Obama participated in the aforementioned telephone press call with national reporters, he did not choose to approach local reporters covering his speech, opting instead to sign copies of his books and work the crowd.

Mr. Obama’s willingness to meet with foreign leaders drew the backing of those present for his speech. “Has not meeting with them done the trick?” asked Paul Bonneville of Tilton, praising the worldliness of Mr. Obama. “How many of them have lived in a foreign country that was not predominately Christian?” he asked of the other presidential candidates.

“I thought it was interesting that he, rather than giving a canned answer, gave a creative answer,” said Jim Monahan of Concord, suggesting that Mr. Obama’s critique of Mrs. Clinton may have struck a chord. “Part of what was really exciting about his speech is the way he was linking the current candidates to the past. If the 2006 election was about change, the 2006 election could be about change on steroids.”

“He rocked the boat,” said Bob MacLellan, a teacher and the chairman of Mr. Obama’s Education Committee in New Hampshire. “He inspired people today,” he added, calling it Mr. Obama’s best speech since the 2004 Democratic National Convention.