Democratic frontrunners John Edwards, Sen. Hillary Clinton and Sen. Barack Obama sparred Sunday night over support for the war in Iraq and the war on terror with Clinton telling Edwards that he was wrong to characterize the latter as a "bumper sticker slogan."

The former North Carolina senator, trailing both Clinton and Obama in national polls, criticized their cautious approach in forcing President Bush to withdraw troops from Iraq.

While some members of Congress spoke out "loudly and clearly" last month against legislation to pay for the war through September but without a withdrawal timetable, "others did not," Edwards said.

• PHOTO ESSAY: Dems Spar Over Iraq in Second Primary Debate

"Others were quiet. They went quietly to the floor of the Senate, cast the right vote. But there is a difference between leadership and legislating," Edwards told his rivals during a Democratic debate.

Both Clinton and Obama voted against the bill — which passed — but without making a strong case against the legislation.

"I think it's obvious who I'm talking about," Edwards said.

Clinton disagreed with Edwards, both in his comments on her role on Iraq and in his characterization of Bush's global war on terrorism as a "political slogan, a bumper sticker."

As a senator from New York, "I have seen first hand the terrible damage that can be inflicted on our country by a small band of terrorists," Clinton said.

Still, she said, "I believe we are safer than we were."

Obama said that the administration's war in Iraq had detracted from efforts to root out terrorists.

"We live in a more dangerous world partly as a consequence of this president's actions," Obama said.

The candidates sought to highlight their own differences on the war in Iraq.

Obama told Edwards, who voted in October 2002 to authorize the war in Iraq but now says that the vote was a mistake: "John, you're about four and a half years late on leadership on this issue."

Obama was not in the Senate at the time of the vote but had voiced opposition to the war resolution at the time.

Edwards conceded, "He was right, I was wrong" on opposing the war from the beginning. And Edwards sought to highlight his change of heart on his vote with Clinton's continuing refusal to disavow her vote for the war resolution.

Said Clinton: "That was a sincere vote."

She again declined to say her vote was wrong.

Edwards chastised Clinton and Obama for waiting till the last possible moment to cast their vote against a bill paying for the troops because it lacked a timetable for withdrawing U.S. forces.

Both Edwards and Clinton agreed that they voted for the war resolution in 2002 without reading an intelligence report on Iraq that was available to them. Both said they sought other information and believed they were thoroughly briefed.

Ohio Rep. Dennis Kucinich said the war on Iraq should not just be blamed on Bush, but on the Congress that authorized it.

U.S. troops "never should have been sent there in the first place," he said. Rather than debate timetables and benchmarks, the Democratic-controlled Congress should "just say no money, the war's over," he said.

Kucinich called on other debate partners who were members of Congress to remember that voters had given Democrats control of both House and Senate last November largely in response to opposition to the war.

To a question on whether English should be the official language in the United States, only former Alaska Sen. Mike Gravel raised his hand in the affirmative.

But Obama protested the question itself, calling it "the kind of question that was designed precisely to divide us." He said such questions "do a disservice to the American people."

All the candidates raised their hands when asked by moderator Wolf Blitzer if they would get rid of the "don't ask, don't tell" policy on gays in the military instituted by President Clinton.

Was it a mistake? Clinton said her husband's 1993 formulation "was a transition policy," but one that is no longer valid.

She said it is being "implemented in a discriminatory manner" and has been used to discharge Arabic linguists when such translators are in short supply.

Asked what role former President Clinton would play in a new Democratic White House, the New York senator said, "Bill Clinton, my dear husband, would be sent around the world as a roving ambassador."

Obama ducked the question. Richardson said he would send the former president to the Middle East as a peace envoy. Gravel said, he would use him as a traveling goodwill ambassador. "He can take his wife with him, she'll still be in the Senate," Gravel said to laughter.

Edwards also challenged Obama, who recently unveiled his health care plan, on the need for universal coverage. Edwards was the first Democratic candidate to offer a proposal and he complained that Obama's plan falls short of offering universal coverage.

Candidates also split on ways to pressure the government of Sudan to end violence in its Darfur region, where more than 200,000 people have been killed in four years of fighting between local rebels and government forces.

Richardson suggested leaning on China — up to a possible threatened boycott of the 2008 summer Olympics — to pressure Sudan to allow in more U.N. peacekeepers.

Clinton declined to say whether she would use military force in Darfur, saying she didn't want to "talk about these hypotheticals."

The candidates squared off as a new national poll found Clinton maintaining a significant lead over her rivals. The Washington Post/ABC News poll found the former first lady leading the field with 42 percent support among adults, compared with 27 percent for Obama and 11 percent for Edwards.

The debate, presented by CNN, WMUR-TV and the New Hampshire Union Leader, took place in the first primary state.

The Associated Press contributed to this report.