Washington » Sen. Bob Bennett's last-ditch effort to persuade Republican delegates to give him another term in office will focus almost exclusively on his seniority in the Senate.

Down in the polls with less than a week before Saturday's convention, Bennett started his new campaign with an e-mail and mailing to GOP activists that ended with this slogan: "Before you vote, know what the consequences are."

The campaign materials focused on his defense of Utah water rights and his work to defeat a land bill pushed by environmentalists.

Bennett told The Salt Lake Tribune his campaign will focus on what Utahns lose if Republican delegates boot him from office in favor of one of his seven challengers, all of whom are touting themselves as more consistent conservatives.

"They will not lose a conservative vote because, frankly, on the big conservative issues, my voting record and my opponents' voting records would be identical," he said. "But what they will lose is the Utah voice on Utah issues."

He argues his replacement would not be in position to stop the impending shutdown of NASA's Ares rocket program, which could result in 2,000 Utahns losing their jobs. He said his replacement wouldn't have his clout to be an effective advocate for Utah's water needs or a sustainable energy plan as the top Republican on the energy and water appropriations subcommittee.

"Utah will lose its voice on energy and water," he said. "We live in a desert and water is vitally important to us."

Brigham Young University political scientist Kelly Patterson said in such a tough fight, Bennett must rely on his three terms of experience.

"It's really the only card he has to play," he said. "The real question is how firmly the delegates believe there is this ideological difference between them and Senator Bennett."

Patterson said Bennett may sway some by touting his power in D.C., but his strategy also comes with an inherent risk. With a general anti-incumbent mood in the nation, Bennett may turn people off by reminding them he's part of the Washington establishment.

"People are frightened that our government leaders are asleep at the wheel," said Tim Bridgewater, one of the leading candidates to unseat Bennett. "A new generation of leaders is, in effect, what the country is clamoring for from coast to coast."

Mike Lee, who is ahead in the delegate race according to recent polls, took issue with Bennett's claim that whoever is elected would vote the same way.

"I don't think it is really accurate," Lee said. "We have identified philosophical differences."

Lee said he wouldn't have voted for the first round of the Troubled Asset Relief Program, or TARP, which Bennett did. He wouldn't have voted to raise the national debt ceiling or for the senior prescription drug benefit known as Medicare Part D.

And Lee is not swayed by the seniority argument either.

"Just because someone has been in office doesn't mean they should stay in office," he said. Lee's final pitch to delegates wont deviate from his focus on the Constitution and a push for limited government.

The delegates will hold three rounds of balloting Saturday. If one of the candidates gets 60 percent of the votes, he or she becomes the Republican nominee. If not, the top two will face off in a June primary.

"The ballot box will determine if experience is more important than bringing new fiscal conservatives to office", Bridgewater said.

Robert Gehrke contributed to this article.