(Adds background on Republican primaries in paras 11-12)
By Nick Carey
LOUISVILLE, May 20 (Reuters) - Facing a challenge from a Tea Party candidate in this year's race to fill his U.S. Senate seat, Mitch McConnell has sought to appeal to conservative Republicans by stressing his pro-gun, anti-immigration and anti-abortion stance. He has also attacked Washington earmarks for lawmakers' pet projects.
It appears to have worked. Going into Tuesday's Republican primary in Kentucky, the Senate minority leader is ahead of his opponent, Louisville-based businessman Matt Bevin, by a wide margin, according to opinion polls.
But once victory is secured, McConnell will have to tack back toward the political center ahead of a tight November contest against Democratic candidate Alison Lundergan Grimes.
He will be on familiar ground. When McConnell sought re-election in 2008 he ran on a record of bringing jobs and federal largesse to his home state of Kentucky, including some of the pork barrel spending be has been arguing against, and was low key about the social issues.
"I wonder if McConnell didn't run scared just a little too long," said Stephen Voss, a political science professor at the University of Kentucky. "He has worked hard to shore up his right flank, but that may have left him exposed."
Although Kentucky tends to vote Republican in national elections, many of the Republican voters in the state's eastern Appalachian counties - which are among America's poorest - are not ideologically conservative. They may be focused more on jobs creation than spending cuts. And issues like abortion or illegal immigration do not resonate much with independent voters and centrist Democrats in a state where registered Democrats outnumber Republicans and the unemployment rate is above the national average.
NOT TO BE UNDERESTIMATED
Opinion polls show Grimes, Kentucky's secretary of state, will be in a very close race with McConnell.
But McConnell's long-term strategy to fend off what might have been a tough challenge from the Tea Party - including raising vast sums of money and building his own grassroots network to rival the Tea Party's - shows he should not be underestimated.
Bevin has raised $3.7 million, and national groups like the Senate Conservatives Fund have spent around $1.7 million supporting him. Backers of the Tea Party, from Kentucky and nearby states have gone door to door, with the United Kentucky Tea Party putting 1,000 volunteers out on the streets.
"This is ground zero for the conservative movement," said Katherine Hudgins of the 9.12 Project Tennessee, a volunteer who traveled to southern Kentucky.
But however much the Tea Party, a movement advocating small government and fiscal austerity, may have shaken up the Republican Party, it's hard to defeat a sitting senator in a primary.
Tea Party-backed candidates knocked off Indiana's Richard Lugar in a 2012 primary and defeated incumbent Bob Bennett in a 2010 Utah state convention. The movement's most prominent figures, such as Senator Ted Cruz, have won office in open primaries where there were no incumbents.
And McConnell undercut Bevin's challenge with a crucial endorsement from Tea Party darling Rand Paul, the junior senator from Kentucky who McConnell worked hard to get elected in 2010 after Paul won his Republican primary
McConnell spent $9.2 million through April 30 but still had $10.1 million cash on hand. Beyond the typical TV spending, he has invested stoutly in retail politics, mobilizing precinct captains in most of the state's roughly 3,600 precincts.
CLOSE RACE AGAINST GRIMES
McConnell will likely focus on economic issues as he faces off against Grimes. Her "pocketbook issues" include raising the minimum wage and equal pay for women, according to her campaign manager, Jonathan Hurst.
McConnell expects to focus on his support for more coal-fired power plants - Kentucky is a leading coal-producing state - a push for repeal of Obamacare, and tax reform, campaign officials said.
According to government data since 1990, Kentucky has ranked in the bottom 10 U.S. states in terms of per capita income. University of Louisville political science professor Jasmine Farrier said that Kentucky voters want a senator who will advance the interests of the state, even more so given that Rand Paul appears to be gearing up for a presidential run in 2016.
"With one senator in Paul whose mind is clearly elsewhere voters here want someone who will be focused on working to further Kentucky's economic interests," she said.
McConnell's part in the Congressional gridlock that has defined Washington during President Barack Obama's time in office is viewed very differently on the right and the left. It has not been unusual to see one commercial in Kentucky from conservatives bashing McConnell for caving to Obama on legislation, followed immediately by one from the Democrats blaming McConnell for preventing anything from getting done in Washington.
The nonpartisan Cook Political Report says in a March report on Kentucky that the November campaign could be "the closest race in the country."
But McConnell, 72, has fought tough re-election races ever since he was first elected to the Senate in 1984.
Grimes, meanwhile has had a boost from the last Democratic presidential candidate to win Kentucky, Bill Clinton, who has campaigned here for her.
Grimes, 35, had $4.9 million in cash at the end of April, of $8.1 million raised by then. She has been building her own network for a "strong, solid field operation" that includes thousands of volunteers statewide, said Hurst. (Reporting By Nick Carey; Editing by Frances Kerry, Martin Howell)