WASHINGTON – President Bush and Senator Kerry skirmished furiously on the campaign trail yesterday over the war on terror and the future of Social Security. Mr. Bush scored his Democratic challenger for employing “shameless scare tactics,” and Mr. Kerry accused the president of engaging in “arrogant boasting” about Iraq.

The exchanges by the candidates coincided with the emergence of new fears about the efficiency of Florida’s voting system. Computer problems plagued the start yesterday of early voting in the Sunshine State, raising the unnerving prospect of another voting debacle there.

Florida election officials conceded that nine of 14 polling stations in Broward County, one of the two counties at the center of the voting dispute four years ago, were having difficulties with a database connection used to ascertain whether voters are properly registered.

In Florida’s Orange County, there were also glitches, with the touch screen system crashing, preventing for several hours voters in Orlando and its immediate suburbs from taking advantage of state laws allowing them to cast their ballots early. State officials insisted yesterday that the snags were just teething problems and by polling day in two weeks the system would be working smoothly.

Lawyers for both parties said, however, that the hitches augured badly for a problem-free election night in the Sunshine State.

On the campaign trail in New Jersey, Mr. Bush said he hoped there would be no repeat of the disputed election of four years ago. He said it was his aim to try to turn out as many GOP voters as possible to minimize the chances of any legal challenges.

The president responded tartly to the accusation by Mr. Kerry Sunday that Mr. Bush is planning a “January Surprise” if re-elected, involving the jeopardizing of Social Security for retirees. The president condemned the Massachusetts senator for engaging in “old-style politics.”

“He’s trying to scare our seniors. It is wrong to try to scare people going into the polls,” the president said.

“One of the things that we obviously are being confronted with are shame less scare tactics,” Mr. Bush told the Associated Press while campaigning in the Garden State.

In the interview on Air Force One with an AP reporter, Mr. Bush cited the military draft as well as Social Security as an area where he thinks his opponent is trying to frighten voters.

“My opponent has said to youngsters that if George W. is elected – re-elected – there will be a draft,” Mr. Bush said. “The American people heard me in the debate say clearly we will not have a draft. We will have an all-volunteer Army.”

Later, at a campaign stop in Marlton, Mr. Bush joked that it “may be a surprise for some people to see a Republican candidate in New Jersey.” The Garden State hasn’t gone to the GOP presidential nominee in the past four elections, but the Bush campaign believes that the state, which lost more residents than any state other than New York in the September 11 terror attacks, is in play.

National security and terrorism are the top campaign themes in New Jersey.

Mr. Bush told an enthusiastic crowd yesterday that Mr. Kerry was locked in a pre-September 11 view of the world, a mind-set that he called dangerous.

“This kind of September 10 attitude is no way to protect our country,” the president said.

He described the Clinton administration’s approach to terrorism as “piecemeal and symbolic” and said: “That is a time that my opponent wants to go back to … a time when we still thought terrorism was only a nuisance.”

Meanwhile, in Florida, where Mr. Bush arrived in the afternoon, Mr. Kerry launched a blistering attack to cheers, accusing the president of mismanaging the war in Iraq.

“Mr. President, your management or mismanagement of this war, your diversion from Al Qaeda and from Osama bin Laden, your shift of the troops to Iraq when there was nothing to do with Al Qaeda, nothing to do with 9/11, has made America less safe, not more secure,” Mr. Kerry said.

The Democrat referred to a report in which the American commander in Iraq, Army Lieutenant General Ricardo Sanchez, complained last winter about critical shortages of spare parts and body armor.

“Despite the president’s arrogant boasting that he’s done everything right in Iraq and that he’s made no mistakes,” Mr. Kerry said, “the truth is beginning to come out and it’s beginning to catch up with him.”

“I will never be a commander in chief who just cavalierly, ideologically, and arrogantly dismisses the advice of our best military commanders in the United States,” the senator said.

The Democratic nominee received a boost yesterday from a surprising quarter.In an interview with Britain’s Financial Times newspaper, a former national security adviser to the first President Bush, Brent Scowcroft, was quoted as saying current tensions in trans-Atlantic relations were due to the Bush administration’s unilateralist positions after September 11.

“We had gotten contemptuous of Europeans and their weaknesses,” Mr. Scowcroft said. “We had really turned unilateral.”

He suggested that recent efforts to persuade the United Nations and NATO to get more involved in Iraq were “as much an act of desperation as anything else to rescue a failing venture.”

While the two candidates traded barbs, a new round of opinion polls found Mr. Bush gaining ground among low-income and urban voters as well as among Americans under age 50,groups that tend to favor the Democrats.

Three polls released Sunday gave Mr. Bush the lead, by margins ranging from four to eight percentage points. A Reuters/Zogby tracking poll released yesterday, however, found the candidates deadlocked at 45% each. Two days ago that tracking poll gave Mr. Bush a four-point lead. The pollster John Zogby says he expects the lead to change back and forth in the remaining two weeks of the campaign.

The snags with the early voting in Florida prompted criticism of the state’s governor, Jeb Bush, from some Democrats. But Rep. Kendrick Meek, chairman of Mr. Kerry’s Florida election campaign, said the additional time before Election Day should allow any problems to be resolved. Democrats are deploying more than 40,000 volunteers to help get out the Kerry vote in the state.

Lawyers working for both parties say they fear a close finish in Florida or any other key state will trigger a welter of legal challenges, delaying an election result. At the weekend, a Bush campaign attorney, Tom Josefiak, warned: “If it is a close election in any one state, it may be days or weeks before we know who the actual winner is.”

Early voting also began yesterday in Texas, Colorado, and Arkansas.