BATON ROUGE, La. -- Republican John McCain leads among Louisiana voters whether he faces Democrats Hillary Clinton or Barack Obama in the fall presidential election, according to new poll results released Monday. But McCain does much better in a matchup against Obama and faces a tougher race with Clinton in Louisiana.

(AP Photo/Bill Haber)

Republican presidential hopeful Sen. John McCain, R-Ariz, at a news conference in New Orleans last year.

Meanwhile, Democratic U.S. Sen. Mary Landrieu has a significant lead over the Republican challenger for her seat in this fall's election, state Treasurer John Kennedy, in the poll results. Fifty percent of those polled by Southern Media & Opinion Research picked Landrieu over Kennedy. Kennedy had 38 percent support.

Pollster Bernie Pinsonat said people still don't know Kennedy as well as Landrieu, but he said Landrieu's high approval ratings with voters -- 70 percent of those polled said they had a favorable impression of her -- make her a formidable candidate.

"It means the voters obviously have a very high regard for her as their U.S. senator," Pinsonat said. "She is going to be tough to beat because she is so well-thought of."

Pinsonat said Landrieu benefited from her prominence in Washington relief and recovery aid for the state since hurricanes Katrina and Rita.

Neither candidate has begun much public campaigning, rather concentrating on fundraising so far. It's unclear if any other Republicans will enter the race, though there has been speculation that several prominent GOP officials are considering it. Kennedy switched parties last year, becoming a Republican. He had run for the U.S. Senate in 2004 as a populist Democrat.

The party primary election is scheduled for Sept. 6 and the general election is Nov. 4.

When questioned about the fall presidential race, nearly 49 percent of poll respondents chose McCain against Clinton, who was the pick of just under 42 percent. The rest were undecided. Against Obama, McCain picked up nearly 51 percent support, compared to 35 percent for Obama and 14 percent undecided.

The telephone survey, of 600 likely Louisiana voters, was conducted from March 26 through April 9 and had a margin of error of plus or minus 4 percentage points.

Pinsonat said he was surprised how much support Clinton received from voters.

"I don't know that she would carry Louisiana, but McCain would certainly have to come in here and campaign to win it. It's certainly not a cinch," the pollster said.

White voters made much of the difference. Clinton had more support from white voters than Obama received in the poll. In head-to-head matchups against McCain, Clinton received just over 26 percent support from white voters, while Obama received only 16 percent support from the white voters surveyed.

"Race is obviously entering into the extremely poor numbers he's receiving from white voters," Pinsonat said.

(Copyright 2008 by The Associated Press. All Rights Reserved.)