Senate Minority Leader Thomas A. Daschle (D-S.D.) is carefully picking his way around patches of political quicksand in the final weeks of the congressional session, with Republicans poised to pounce on any missteps that could be used against him in his tight race for reelection.

Concerned about Daschle and other Democrats in close races in conservative-leaning states, Senate Democrats have indicated they are unlikely to employ the kind of confrontational tactics -- especially on issues such as homeland security and taxes -- that contributed to election losses two years ago.

Republicans sense that they have Democrats "over a barrel," as Rep. Thomas M. Davis III (R-Va.) put it last week. They appear likely to press their advantage, especially on the bill to reorganize the nation's intelligence agencies. That measure is likely to dominate Congress during the next two weeks before its planned recess for the elections.

In South Dakota, Republican John Thune, a former House member who narrowly lost the Senate race in 2002, has targeted Daschle on Iraq, energy policy and, more recently, the senator's opposition to a proposed constitutional amendment authorizing Congress to ban physical desecration of the U.S. flag.

Daschle "has got a lot of minefields to walk through in the waning days of the session," Thune's Senate campaign manager, Dick Wadhams, said.

Daschle and other Democrats averted a potentially bruising pre-election fight over taxes by agreeing to a five-year extension of three tax cuts aimed at the middle class, even though many Democrats winced at some of the provisions, including more business tax breaks and omission of expanded tax refunds for poor families.

While some senators of both parties wanted a shorter extension, Daschle signaled he could support five years, effectively ending any efforts to change the bill significantly. The bill was overwhelmingly approved late Thursday with only Democrat Ernest F. Hollings (S.C.) and Republicans Lincoln D. Chafee (R.I.) and Olympia J. Snowe (Maine) in dissent.

Chafee said he was disappointed but not surprised by senators' lack of insistence on pay-as-you-go provisions, another goal of many Democrats as well as some Republicans, under which the tax cuts would have been offset by revenue increases or spending reductions. "These are popular tax cuts. . . . I saw it coming," Chafee said.

A potentially more dangerous issue for Democrats arises with legislation to revamp intelligence and anti-terrorism operations, propelled by recommendations of the independent Sept. 11 commission.

The Senate, which will consider its version of the legislation next week, has gone out of its way to produce a bipartisan bill. But the House bill is being drafted only by Republicans, who have included controversial provisions expanding the powers of law enforcement agencies and making it easier to deport immigrants who have run afoul of the law. On this and other points, the bills are different enough to ensure difficult House-Senate negotiations on a final version.

Furious over being sidelined in negotiations over major bills last year, Senate Democrats have held up conferences on some key bills this year to force negotiation of "pre-conference" agreements or win other assurances that Senate GOP leaders would not crumple under pressure from House Republicans and the White House.

But Democrats vividly remember the political fallout from the 2002 debate over legislation creating the Department of Homeland Security, when Democrats held up final action in an attempt to force stronger employee protections. During that year's campaign, Republicans defeated Sen. Max Cleland (Ga.), who lost three limbs during the Vietnam War, with the help of ads questioning Cleland's patriotism because of his vote with fellow Democrats to hold up passage of the homeland security bill.

Daschle said last week he was reserving judgment on whether to demand a pre-conference agreement or other conditions before allowing the intelligence bill to go to conference. But colleagues said he was not likely to do so. Republicans may be hoping for a deadlock they can blame on the Democrats, said a Democratic aide who declined to be named because of office policy. "We aren't going to play their game," he added.

In South Dakota, Republicans are prepared for Round 2 on homeland security if Democrats hold up the bill. "Two years ago, they delayed the Department of Homeland Security bill, and it blew up in their faces," Wadhams said. "It has the makings of a disaster again. The only difference is that [Daschle's] name is on the ballot this time."

Meantime, Thune is bearing down on the flag issue, even though Senate Republicans -- a vote or two short of the two-thirds required for a constitutional amendment -- appear uncertain about scheduling a vote before the elections.

At news conferences Wednesday, Thune called on Daschle to reverse his position opposing the flag amendment, just as Daschle was setting up a telephone news conference with four former military officials who supported Daschle and denounced Thune.

Dan Pfeiffer, deputy manager and spokesman for Daschle's campaign, questioned the efficacy of the tactics of Thune and the Republicans.

"People inside the Beltway often have an inflated sense of the impact of what happens in Washington," Pfeiffer said. "There's a great disconnect between what's talked about in the salons of Washington and [over] the kitchen tables of South Dakota."

Besides, he added, "You don't spend a lot of time worrying about what is actually happening, because they will make it up anyway."

Thomas A. Daschle's role as minority leader is a target for his GOP opponent.