Party leaders are locked in a death struggle to hold their ground in the closely divided Congress and add the extra seats necessary to shake up the political balance. The battle has already turned personal with allies of President Bush going so far as to compare Majority Leader Tom Daschle to Iraqi leader Saddam Hussein. “And Saddam is offended,” Daschle quipped at a recent dinner, trying to make light of the campaign against him. But the attacks have taken their toll. Daschle seems less willing to take positions that could create problems for Democrats running for reelection in states Bush won by large margins.

Republicans have more Senate seats to defend, 20 compared to the Democrats’ 14. But the numbers don’t tell the whole story. Democrats have more vulnerable seats, beginning with South Dakota where freshman Sen. Tim Johnson faces a spirited challenge from popular Rep. John Thune in a race that pits Bush against Daschle, and tests the power of Bush’s war presidency. If Thune had followed his original game plan, he would have run for governor. But the White House, eager to win the seat and embarrass Daschle in his home state, persuaded Thune to take on Johnson.

Thune dredged up some long-ago votes Johnson cast against military spending in the House as a way to question his commitment to Bush’s war budget. In an exchange of television ads, Johnson pointed out that his son is serving in Afghanistan, and he would never undermine his son’s security, or the nation’s. Thune reminded voters that he was the son of a World War II veteran, as though the voters would decide based on these family ties.

Republicans are most worried about Arkansas, where freshman Sen. Tim Hutchinson is widely regarded as heading to defeat. Hutchinson was a family-values champion during the Clinton impeachment fight, and so it didn’t sit well with the voters when he divorced his wife and married a staffer. Atty. Gen. Mark Pryor, son of former Senator David Pryor, is a quality candidate for the Democrats.

Another vulnerability for the Republicans is New Hampshire, where Gov. Jeanne Shaheen is poised to capture the Senate seat held by Republican Sen. Bob Smith. A better candidate for the GOP would be Rep. John Sununu, a personable conservative and son of former New Hampshire Gov. John Sununu. But Sununu has had trouble raising money, and the White House, fearing a backlash from Smith backers, has stayed out of the race. Smith is likely to prevail among GOP loyalists despite a brief bid for the presidency as an Independent that raised questions about his party loyalty.

Missouri, Minnesota and Iowa are trouble spots for the Democrats. In Missouri, freshman Sen. Jean Carnahan will be up against historical odds in trying to win on her own the seat she was awarded when voters elected her dead husband. In Minnesota, liberal Sen. Paul Wellstone always runs a tight race, and this will be a squeaker, win or lose. Iowa’s Tom Harkin is on the GOP’s target list, and he faces an especially capable challenger this time around in Rep. Greg Ganske, a plastic surgeon who has won many admirers in the state with his independent stands. He broke with his party on campaign finance reform, and he was one of only four House Republicans to oppose President Bush’s tax cut.

Holding the Senate means trench warfare, yet the Democrats will gain a seat or two. The House is harder to predict. Absent any galvanizing issue, a major swing to either party is unlikely, which means the Republicans should hang on to their majority.

Political Correspondent Eleanor Clift contributed to this column.