President Bush flew home to Texas tonight for the finale of his 16-month effort to tip the Senate back to Republican control, as his aides began expressing optimism about the outcome for the first time in weeks.

Bush has so much riding on Tuesday's elections that his five-day, 15-state closing swing had the feverish pace of the last hours of a presidential campaign, with "W" and "Women for Bush" banners spanning the arenas.

"These elections, they're kind of tight," Bush said in Cedar Rapids, Iowa. "And a tight election means you can have a tremendous influence on who wins." He then urged the GOP activists to get people to the polls and "not only encourage them to vote, but encourage them to vote for the right person."

Bush used his last day on the road to boost four Senate candidates who have benefited all year from presidential visits and fundraising: Rep. Greg Ganske in Iowa, Jim Talent in Missouri, Sen. Tim Hutchinson in Arkansas and John Cornyn in Texas. Cornyn has a slim lead, while Ganske is far behind. White House officials are optimistic about Talent and doubtful about Hutchinson.

"A lot of those political pundits, the big talkers, have said to the world, 'Hutchinson can't win,' " Bush said in Bentonville, Ark. "Get out the vote, work hard and you'll be surprised at what's going to happen come Tuesday."

A key question for Bush will be whether his administration-wide campaign effort has been worth the cost. He spent day after day in hotel ballrooms amid burgeoning world crises, diverted political capital that might have been used on his immediate legislative agenda, and outdid President Bill Clinton in time and effort devoted to the nitty-gritty of party politics. Bush's approval rating slid in most polls as the campaign intensified.

The pace took a toll on Bush, who was described by a close aide as grouchy about the schedules. Bush was tired and coming down with a sore throat over the weekend, although he was said to be better today.

White House officials profess no regret, mostly because they know they would have been judged on the results of the races regardless of how much effort they had expended. "Given the popularity of the president and the yearning by the campaigns to have him, staying home was not an option," press secretary Ari Fleischer said. "That would have alienated the party."

The pre-election results looked mixed. Bush failed to build a lead for several of the campaigns he cared about most, including Senate races in South Dakota and Minnesota. Although past administrations have hesitated to make repeat visits to key states in the final hours because they could suck energy away from get-out-the vote efforts, officials from the tight GOP Senate races said they were grateful to Bush for firing up poll workers and conservative voters.

White House officials hesitated to forecast key races. In 2000, Karl Rove, Bush's top political adviser, predicted to the campaign press corps that Bush would trounce Vice President Al Gore by a huge margin of electoral votes, which Democratic operatives still deride as his "inevitability gambit." White House officials studiously avoided that approach in the last few weeks, partly because they were genuinely uncertain about the outcome.

Heartened by several polls in the past two days, Fleischer told reporters on Air Force One today that Bush is "hopeful that Republicans will have big day," thwarting the historic pattern of midterm losses for the party in power.

"All signs give a lot of reason to be optimistic that the trend can be broken," Fleischer said. Hedging, he added, "I think it remains an open question about whether or not Republicans pick up seats."

The White House today distributed a fact sheet to Republican pundits and officials who will be appearing on television this week giving "historic context" for the election, pointing out that the average number of House seats lost by the president's party in midterm elections in the past century is 30. But in 1998, when Clinton was on the brink of impeachment, his party gained five seats.

Bush aides said their mood had swung from giddy optimism when it looked as if they would unseat Sen. Robert G. Torricelli (D-N.J.), to pronounced pessimism when he was replaced by a stronger candidate and a GOP pickup no longer looked possible. Officials said they suffered a psychological blow when Bush's brother, Florida Gov. Jeb Bush (R), began to look vulnerable in his reelection race a few weeks ago, but he appears to have recovered. Top officials said today that they are guardedly optimistic about retaking the Senate, since polls have detected no late-breaking Democratic tailwind. "If you had a big win, no one would be surprised," one official said.

Bush's aides know the results of the races where Bush worked hardest will be treated as a referendum on his clout and policies, and Fleischer tried to preempt sweeping conclusions. "There are a lot of local factors," he said. Fleischer said Rove updates Bush once a day on polls from critical states. "There's only so many ways you can say, 'It remains close,' " he said.

Aides said Bush went for a morning run on the treadmill in an aide's hotel room in Cedar Rapids, where the streets had been blocked by combines and road graders for security. Bush called Mexican President Vicente Fox to discuss the U.N. resolution on Iraq before speaking at a 9 a.m. rally.

Bush was joined for his last stops by Laura Bush, and led each crowd in saluting her 56th birthday. Tuesday is their silver wedding anniversary.

After staying overnight at his ranch in Crawford, Tex., Bush will fly back to Washington to eat dinner and watch returns in the White House residence with a few Republican leaders and their wives.

President Bush visits Cedar Rapids, Iowa, to boost GOP candidates. He is joined by gubernatorial candidate Doug Gross, left, Rep. Jim Leach and Rep. Greg Ganske, right.