President Bush warned on Saturday that Saddam Hussein could strike without notice and inflict "massive and sudden horror" on America, offering a new rationale for pre-emptive military action against Iraq.

In the run-up to key congressional votes on war-making authority, Bush promised in the clearest terms yet to rebuild Iraq after a war. He also said the Iraqi president has a "horrible history" of attacking his enemies first.

"We cannot ignore history. We must not ignore reality. We must do everything we can to disarm this man before he hurts one single American," Bush told hundreds of cheering police and National Guardsmen at a Manchester, N.H., rally. A leading Democrat, Senate Majority Leader Tom Daschle, strongly challenged the "strike first" policy as Bush toured this politically important state.

The president's remarks reflect subtle changes the White House is making in its case against Saddam as Bush prepares to address the nation Monday night from Cincinnati.

Advisers say the address -- now in its fifth draft -- seeks to synthesize the case against Saddam, the reasons war may be necessary and why the threat is imminent.

Bush and his advisers were tinkering with the speech during a weekend stay at his parents' home in Kennebunkport, Maine. He made a quick visit to New Hampshire to address soldiers and police officers, then headline a $500,000 fund-raiser for GOP Senate candidate John Sununu. The congressman's father was White House chief of staff for Bush's father.

Sentiment of some Southeast Missouri residents is on the president's side. Iraq's lack of cooperation regarding U.N. inspections is reason enough to go to war, said Denise Dirnberger of Oran, Mo.

"All we want to know is what's going on over there, and for them to let our inspectors in."

Shane Thompson of Sedgewickville, Mo., said he is willing to trust Bush's leadership on the issue.

"If it's anything that would threaten the United States now or in the future, I would support anything we need to do," he said. "I leave it up to our government and if they think we need to go, we need to go."

David Black of Jackson believes choosing to confront Saddam is the lesser of two evils when compared with inaction.

"I guess as bad as war is, if the end result of going over there would be less damaging than Saddam having all these weapons, then I'd be in favor of it."

New Hampshire support

In a state whose motto is "live free or die," GOP donors jumped to their feet when Bush said of Saddam, "For the sake of peace, for the sake of freedom, for the sake of our future and our children's future, we will disarm him."

Bush won agreement last week with a bipartisan group of House leaders for a resolution allowing him to use force against Iraq. Senate Democrat are more skeptical, though a resolution is expected to pass as early as this week.

"Pre-emptive strikes are something we have to take very, very seriously and carefully," Daschle, D-S.D., said Saturday on CNN. "Number one, what kind of a standard does it set for the rest of the world? If it's OK for us, is it OK for India? How about Russia? How about Israel?"

Daschle said the House resolution gave Bush too much latitude to wage war. He questioned whether there is enough evidence that Iraq poses an imminent threat and said Bush has failed to explain how Iraq would be rebuilt after war.

"How long will we be there? What will it entail, on the part of the United States? How much will it cost? Who will be involved?" Daschle asked.

Bush's struggle to pass a tough U.N. resolution on Iraq was underscored Saturday when Russian Foreign Minister Igor Ivanov said the return of weapons inspectors to Iraq should not be delayed. Bush wants the mission postponed while he presses for a new U.N. mandate.

"The message to Russia is this is about peace, this is about how to preserve peace, by removing the greatest threat to peace," White House spokesman Ari Fleischer said, offering a new rhetorical twist likely to be appear in Bush's Monday address to counter critics who say the president is too hungry for war.

In a preview of that speech, Bush tried in Manchester to address the issues raised by Daschle and other skeptics.

On the question of launching pre-emptive action, Bush laid out his usual case against Saddam: The Iraqi leader produces weapons of mass destruction, consorts with terrorists, oppresses his own people and condones abuses against the wives and daughters of his political opponents.

But then he added a new rationale, suggesting Saddam might strike first if not disarmed.

"The regime is guilty of beginning two wars. It has a horrible history of striking without warning," Bush said in his weekly radio address.

"Delay, indecision, and inaction are not options for America, because they could lead to massive and sudden horror."

While other administration officials have talked about efforts to bring democracy and stability to a post-Saddam Iraq, Bush has had little to say about his post-war intentions.

"Should force be required to bring Saddam to account, the United States will work with other nations to help the Iraqi people rebuild and form a just government," Bush said. Aides said it was his most firm commitment yet, though it came with no details.

Bush said a congressional resolution would help persuade skeptical world leaders to back a tough new U.N. resolution on Iraq.

"I urge Americans to call their members of Congress to make sure your voice is heard," Bush said.

On a separate issue, Bush chastised Senate Democrats for demanding collective bargaining rights for workers in the proposed Homeland Security Department. Bush said inflexible union protections would "prohibit us from doing the job of protecting the American people."

Firing back, Daschle accused Republicans of "trying to bust the unions" and wanting to return to the days when presidents "could pick their political hacks and put them in government positions."

At the fund-raiser, Bush tried to help Sununu retain his lead over Senate rival Jeanne Shaheen, the state's Democratic governor. With taxes a gathering issue in state races here, Bush defended his tax cuts.

"For the sake of economic vitality in this state, you will need a United States senator who will join me in making the tax cut permanent," Bush told GOP donors.