Hillary Clinton sounded the themes of hope and opportunity in a speech Saturday boosting the re-election campaign of U.S. Sen. Mary Landrieu, D-La., who goes before voters Tuesday in a bid for a fourth six-year term.

“Go out over these next three days and tell everyone you can reach to vote their hopes, not their fears — to vote their dreams,” Clinton, a former first lady and U.S. secretary of state, told an audience of several hundred Landrieu supporters in New Orleans. “Because when Americans are at their best, there are no limits to what we can accomplish.

“I believe that. Mary believes that. Give her three days for six more years.”

Voters Tuesday will choose among Landrieu and seven other candidates in the open primary for the U.S. Senate. If no candidate wins a majority of the votes and an outright victory, the top two finishers will meet in a Dec. 6 runoff.

Polls consistently show Landrieu and Republican U.S. Rep. Bill Cassidy, of Baton Rouge, atop the primary field but with each short of 50 percent. Tea party Republican Rob Maness, of Madisonville, is a respectable but distant third.

Landrieu, whose 2008 election was the last time a Democrat won a statewide race in Louisiana, is a prime target of the nationwide Republican effort this fall to pick up the six seats the party needs for a Senate majority. The race has attracted national attention and millions of dollars in outside spending on political ads.

Landrieu hopes Clinton will help boost turnout of Democratic voters Tuesday. A high turnout of Democratic voters — many of whom skip midterm elections, when there is no presidential race commanding attention — is critical to Landrieu’s chances.

Clinton also could be seen as a spur to participation by women voters, a group that has tended to favor Democratic candidates. A poll released Thursday by the University of New Orleans showed a moderate gender gap in the Tuesday primary, with women favoring Landrieu over Cassidy by 39 percent to 34 percent.

Clinton, regarded as the early favorite for the Democratic presidential nomination in 2016, contrasted Landrieu’s support for equal pay for equal work, for laws aimed at preventing violence against women and for increasing the federal minimum wage, which she said is now earned by more women than men, with the positions of her Republican opponents.

The Republicans, Clinton said, “stake everything on fear. Fear is the last resort of people who have run out of ideas and run out of hope. Fear is not going to help us come together to solve our problems.

“What you want is someone like Mary who has proven she is fearless on your behalf.”

Clinton also noted Landrieu’s support for increasing federal financing and reducing loan interest rates for college students — issues with appeal to young voters, another Democratic-leaning constituency that includes many occasional voters.

Clinton served alongside Landrieu for eight years in Washington as a senator from New York, and there, she said, she witnessed what Landrieu has emphasized in her campaign: that Landrieu fights “tirelessly, relentlessly” for Louisiana interests.

“Her passion for this state is so palpable,” Clinton said. “Every single issue she thought would affect her state, she was in the forefront of addressing.

“Mary’s been tested. This is a woman with a big heart and a spine of steel. And that’s what Louisiana needs and deserves.”

Before Clinton’s 20-minute speech, Landrieu addressed the crowd for about half as long. The rally was billed as “Moms & Grams for Mary,” and Landrieu noted that both she and Clinton are now grandmothers. She mentioned that her father, former Mayor Moon Landrieu, was in the audience and said, “My dad knows how stubborn I can be.”

She took aim at Cassidy and his support for increasing the Social Security retirement age to 70. “Send me back to keep him from wrecking Social Security and Medicare,” she said.

Warm-up acts included several Louisiana Democratic politicos: former U.S. Sen. John Breaux; former Gov. Kathleen Blanco; U.S. Rep. Cedric Richmond, of New Orleans; Mayor Mitch Landrieu, who is the brother of Sen. Landrieu; state Sen. Karen Carter Peterson, the state party chairwoman; state Rep. Helena Moreno, of New Orleans; and City Council members Stacy Head and LaToya Cantrell. U.S. Rep. Sheila Lee Jackson, D-Texas, also spoke.

The late-afternoon event campaign rally took place in the Sugar Mill building across Convention Center Boulevard from the Ernest N. Morial Convention Center.

Follow Gregory Roberts of The Advocate Washington bureau on Twitter, @GregRobertsDC.