By Debbie Hummel
SALT LAKE CITY, Utah (Reuters) - Veteran U.S. Senator Orrin Hatch faces what may prove to be the toughest re-election bid of his 36-year tenure, as he battles a challenge on Thursday by two younger Tea Party candidates in Utah's Republican caucus.
Heavily Republican Utah last elected a Democrat to the U.S. Senate more than four decades ago, so the victor in the state's Republican party contest is usually considered the presumptive winner of the general election in November.
For a senior stalwart of the Republican mainstream like Hatch, the ranking Republican on the tax-writing Senate Finance Committee, an incumbent seat in the U.S. Senate has long been seen as his to lose. He was first elected in 1976, turns 78 next week, and says this next term will be his last.
But he is fighting to avoid the fate of his former Senate colleague, Utah's 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.
The Tea Party movement has sought to unseat Republicans who do not share their fiscally-conservative ideals of smaller government and less taxation. Former state Senator Dan Liljenquist, 37, and state Representative Chris Herrod, 46, are hoping to grab Hatch's traditional spot on the ballot, saying now is the time for change.
"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."
Both challengers have gained a strong Tea Party following with campaign rhetoric focused on 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.
Hatch and his campaign will be closely watching the caucus meetings as the first significant marker of his re-election prospects, although a clear winner may not emerge until the party convention in April, or later if a run-off vote is needed.
EFFORT TO BOOST TURNOUT
Hundreds of caucus meetings will be held throughout Utah on Thursday evening in homes, churches, schools and other locations where registered Republican voters will select 4,000 delegates to represent them at the state party convention on 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, and failed to make it out of the convention. Mike Lee won the primary runoff against the second-place Republican, and ultimately succeeded Bennett in the Senate.
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.
But some longtime Republicans in Utah say the mood in the state was not the same as in 2010, when Bennett was pushed out, and that Hatch has positioned himself well going into the caucus meetings.
"They underestimate how many people he has worked with over the years," said Enid Green Mickelson, a former congresswoman from Utah. "He has always worked hard for his re-election. He's always run like he's opposed."
The caucuses were expected to have a higher than normal turnout as party officials have stepped up precinct training and paid for lawn signs and television and radio ads reminding voters to attend.
They also 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.
Hatch campaign spokesman Dave Hansen said the senator takes every election seriously and was no more or less concerned about his chances than in the past.
"He hasn't approached this one any differently than he has an election before. He wants to be sure he's well prepared," Hansen said.
(Editing By Cynthia Johnston and Tim Gaynor)