By Debbie Hummel
SALT LAKE CITY (Reuters) - Seeking one last term, Republican U.S. Sen. Orrin Hatch is facing what may prove to be the toughest re-election bid of his 36-year tenure, being challenged by two popular and younger Tea Party candidates in Thursday's Utah Republican caucus.
Conservative and heavily Republican Utah last elected a Democrat to the U.S. Senate more than four decades ago, so the Republic nominee is usually considered the presumptive winner of the general election in November.
For a senior stalwart of the GOP mainstream like Hatch, the ranking Republican on the tax-writing Senate Finance Committee, an incumbent seat in the U.S. Senate has long been regarded as his to lose. He was first elected in 1976 and turns 78 next week.
Now Hatch is girding to avoid the fate of his former Senate colleague, Bob Bennett, whose 2010 run for a fourth term foundered over conservative outrage at the healthcare overhaul pushed by President Barack Obama, leading to a revolt against the Republican establishment by state Tea Party activists.
Former state Senator Dan Liljenquist, 37, and state Representative Chris Herrod, 46, are running this year against Hatch, saying now is the time for change.
Both have gained a strong Tea Party following with campaign rhetoric focused on such conservative themes such as reducing the size of government and lowering taxes. They have suggested Hatch's principles have been compromised by his lengthy tenure as part of the inside-the-Beltway establishment.
"It's time for a new generation to step up and lead," Liljenquist said in a recent interview. "Washington will not be changed from the inside."
Hatch has cast his seniority and experience as a plus for Utah, warning the state stands to lose political clout on Capitol Hill if he is unseated.
Even so, the senator vowed on Tuesday to serve just one more term, his seventh, if he manages to prevail over those who would force him into retirement sooner. "I want to make it the best six years anyone's put in for Utah," Hatch said.
The Washington-based political action group FreedomWorks, closely aligned with the Tea Party movement, has spent nearly $600,000 to unseat Hatch this year, according to campaign expenditure filings.
Political watchers and many party faithful expect a more even-keeled mood at Thursday's caucus meetings compared with two years ago, and they anticipate the state Republican Party push to boost caucus attendance will work in Hatch's favor.
TEA PARTY HEAT
"There's certainly a lot of those in the well-organized conservative groups who want to get Sen. Hatch out," said Swen Howard, a legislative district vice-chair for the Republican Party in Davis County, just north of Salt Lake City.
"My sense is if there is a really good turnout, which I expect there will be, it won't be quite the same environment as it was with Sen. Bennett," Howard said.
Party officials have stepped up precinct training and paid for lawn signs and ads on television and radio reminding voters to attend their caucuses, all in a push to increase attendance.
They got a boost from the Mormon church, which asked congregations to refrain from holding church meetings the same night as the party caucuses to avoid scheduling conflicts.
The effort is being lauded by those who have criticized the state's caucus system as one that placed too much political clout in the hands of too few people and was easily swayed by a single, determined faction, as was the case in Bennett's defeat.
State party chairman Thomas Wright said his goal is to achieve a turnout of 100,000 Republicans to the caucus meetings, which would mark a 70 percent increase from 2010's attendance.
The Republican Utah caucuses take place on Thursday with hundreds of meetings throughout the state in homes, churches, schools and other locations where registered Republican voters will select 4,000 delegates to represent them at the state party convention to be held April 21.
A candidate who emerges from the convention with 60 percent or more of the party's delegate vote will clinch the nomination.
If no contender takes 60 percent, the two highest vote getters compete in a primary election on June 26, the same day as Utah's presidential primary.
In 2010 Bennett came in third among delegates, failing even to make it out of the convention. Lee won the primary runoff against the second-place Republican.
(Editing by Steve Gorman and Daniel Trotta)