June 26 (Bloomberg) -- Senator Elizabeth Dole has long been a Republican star: U.S. transportation and labor secretary, spouse of 1996 presidential nominee Robert Dole, and a candidate for president herself in 2000.

Dole was elected to the U.S. Senate from North Carolina in 2002 with 54 percent of the vote, the state's biggest Senate margin in almost a quarter-century. Now, it's Dole's Republican credentials that threaten to undermine her re-election chances.

Considered an easy bet for re-election earlier this year, Dole is facing a tighter race against Democratic state Senator Kay Hagan. Democrats say Dole, 71, now is a leading target in November's elections, as the slumping economy and Iraq war are endangering Republican seats in states that earlier seemed out of reach.

``She's in trouble because of the straight-up fact that she's a Republican,'' Brian Mayberry, a 35-year-old political independent, said June 20 at a Wilmington gas station while pumping $59.73 worth of gasoline into his Chevrolet Trailblazer sport utility vehicle. While ``the consensus is that she's been a good senator,'' Mayberry said he won't vote for Dole because he blames Republican President George W. Bush for high gas prices.

``It's a tough year,'' Dole said in an interview. While voicing confidence she'll win, the incumbent said broad voter discontent may result in a ``tight race.''

Democrats' Prospects

Dole's seat is among a group controlled by Republicans in states, such as Mississippi and Kansas, where polls show improving Democratic prospects. Jennifer Duffy, Senate editor of the nonpartisan Cook Political Report, forecasts that Democrats will gain four to seven Senate seats.

The vulnerability of senators like Dole raises the possibility that an anti-Republican wave may give Democrats the nine seats they need for a 60-40 Senate majority, Duffy said. With 60 votes, Democrats would have filibuster-proof control of the chamber and could defeat Republican efforts to block legislation.

``If things keep going the way they're going for Republicans, it's not crazy to think about nine seats,'' Duffy said.

Matt Miller, a spokesman for the national Democratic Senatorial Campaign Committee, identified Dole as a key target: ``It's clear as we get closer to the election that this has become one of the top battlegrounds in the country,'' Miller said.

Distance From Bush

Dole is trying to minimize her association with the president and promote efforts to work pragmatically for North Carolina voters.

This month, she voted against Bush twice by supporting legislation to curb greenhouse-gas emissions and to reverse planned fee cuts to doctors providing Medicare health services. Last year, she sided with Bush 85 percent of the time on key votes, and in 2003 -- her first year in office -- she backed him 98 percent of the time, according to a study by Congressional Quarterly.

In television advertisements that began running late last month, Dole's campaign doesn't mention Bush or the Republican Party. Instead, the ads cite her efforts to aid tobacco growers with a federal quota buyout, to protect jobs during a 2005 round of military base closures, and to help North Carolina sheriffs fashion a program to deport illegal immigrants who have committed crimes.

Work With Clinton

At a debate June 21 before the North Carolina Bar Association, Dole said she worked with Democratic Senator Hillary Clinton of New York to offer some military families extended time off under the Family and Medical Leave Act. Dole also declined to endorse Bush's call to lift an offshore-drilling ban, saying she needed more time to study the potential impact on North Carolina.

Hagan, meanwhile, is emphasizing Dole's affiliation with the Republican president, criticizing the senator for supporting Bush's policies on the war, tax cuts and other issues.

``I am running because Washington is broken,'' Hagan said during the debate.

Dole led the National Republican Senatorial Committee campaign effort two years ago, when her party lost control of the chamber and trailed Democratic fundraising by almost $33 million.

``Her reputation took a bit of a hit, based on what happened in the 2006 elections,'' said Andrew Taylor, chairman of the political science department of North Carolina State University in Raleigh.

Military Voters

Dole said presumptive Republican nominee John McCain, a former Vietnam prisoner of war and a member of the Senate Armed Services Committee, will have plenty of appeal in a state dotted with military bases, including Jacksonville's Camp Lejeune, the second-largest Marine Corps base in the U.S.

Republicans have carried North Carolina in the last seven presidential elections, and the party's White House candidates had long coattails -- Republican Senate candidates have won six straight contests in presidential years.

This year, Democrat Barack Obama, the first black presidential nominee of a major party, has designated North Carolina as a battleground and Hagan may benefit from a surge in turnout among black voters enthusiastic about Obama's bid. Blacks make up more than one-fifth of the electorate in North Carolina, where Obama got nine out of 10 black votes in the Democratic primary.

``I hope we'll have a lot of Obama supporters who will be supporting Elizabeth Dole for the Senate,'' Dole said.

To contact the reporter on this story: Laura Litvan in Wilmington, North Carolina at llitvan@bloomberg.net

Last Updated: June 26, 2008 00:01 EDT