(AP) -- Hillary Rodham Clinton, making her return to Iowa for the first time since the 2008 presidential campaign, implored Democrats on Sunday to choose shared economic opportunity over "the guardians of gridlock" in an high-profile appearance that drove speculation about another White House bid into overdrive.

"Hello Iowa. I'm back!" Clinton declared as she took the podium at retiring Sen. Tom Harkin's annual steak fry fundraiser, a fixture on the political calendar in the home of the nation's first presidential caucus. Clinton joined her husband, former President Bill Clinton, in a tribute to Harkin that brought them before about 10,000 party activists who form the backbone of Iowa's presidential campaigns every four years.

The former New York senator and first lady did not directly address a potential campaign but said she was "thinking about it" and joked that she was "here for the steak." She later said that "too many people only get excited about presidential campaigns. Look -- I get excited about presidential campaigns, too." But she said the upcoming midterm elections would be pivotal for the state's voters.

"In just 50 days Iowans have a choice to make -- a choice and a chance. A choice between the guardians of gridlock and the champions of shared opportunity and shared prosperity," she said, urging voters to elect leaders who would "carry on Tom Harkin's legacy of fighting for families."

Following a summertime book tour, Clinton was making her biggest campaign splash in 2014 so far, opening a fall of fundraising and campaigning for Democrats who are trying to maintain a Senate majority during President Barack Obama's final two years. The event also served as a farewell for Harkin, a liberal stalwart and former presidential candidate who is retiring after four decades in Congress.

Obama defeated Clinton in the state's leadoff presidential caucuses in January 2008 -- Clinton finished third behind the future president and then-North Carolina Sen. John Edwards -- and the visit marked the former secretary of state's first appearance in Iowa since the campaign.

The Clintons pressed Democrats to support Rep. Bruce Braley, who faces Republican state Sen. Joni Ernst in a competitive Senate race. Mr. Clinton, who faced Harkin in the 1992 presidential primaries, praised the retiring senator's work on health care and people with disabilities.

"You know what you ought to do to honor the Harkin legacy is elect Bruce Braley," the former president said.

Hillary Clinton, who would become the first female president if she runs and wins the presidency, used her speech to strike a chord on women's issues, citing the need to elect candidates who would allow women to make their "own health care decisions" and promote equal pay for equal work.

She also lauded Obama's economic record, noting the increase in exports for the state's farmers, Iowa's low unemployment rate and a boost in the production of renewable energy. Her address also offered references to her husband's economic mantra of helping people who "work hard and play by the rules."

Harkin praised Clinton's longtime commitment to health care overhaul, which passed while she served as Obama's secretary of state. "Her fingerprints are all over that legislation. It would not have happened but for her strenuous advocacy all those years," he said. Republicans have vigorously opposed the so-called "Obamacare" law and sought to connect Clinton to Obama's signature legislation.

Attending Harkin's final bash, party activists streamed onto a hot-air balloon field lined with colorful signs thanking the Harkins and promoting state candidates. Ready for Hillary, a super PAC supporting a potential Clinton candidacy, posted light blue "Ready" signs.

"I honestly believe she will be the next president," said Cindy Sturtz, a union member from Fort Dodge, who caucused for Obama in 2008 but said she plans to support Clinton if she runs again.

Before taking the stage, the Clintons took turns flipping steaks at a grill before a large media contingent. "I'm just flipping for other people now," joked Bill Clinton in a nod to his wife's headliner status. Hillary Clinton nodded in approval: "This looks really good!"

The couple spoke briefly to reporters, remaining coy about her future plans. Hillary Clinton, asked if she planned to run for president, said, "There are a lot of people running right now." She pointed to the need to help Democrats in 2014. "We're going to be doing a lot. And we've already started. There's so much at stake."

Bill Clinton noted that daughter Chelsea Clinton is expecting her first child soon. "I cannot be baited," he said, asked whether his wife would run for president again. "I'm waiting to be a grandfather."

Harkin called the Clintons part of the state's "Democratic family." He recalled Bill Clinton's famous "Comeback Kid" moniker during the 1992 campaign. Bill and Hillary Clinton, he said, are "now the 'Comeback Couple.'"

When the event ended, people chanted, "Hillary, Hillary, Hillary," and she waded into the throng awaiting her at the bottom of the stairs. Clinton shook hands and signed copies of her book and "Ready for Hillary" posters.

Clinton, who has conferred with Iowa Democrats in recent days, would enter a presidential campaign with a large advantage over potential rivals. Early polls have shown her leading other Democrats, including Vice President Joe Biden and Maryland Gov. Martin O'Malley, by wide margins.

Biden is traveling to Des Moines next week and has not rejected the possibility of another campaign, while O'Malley has made several visits to the state and dispatched staffers to Iowa this fall. Independent Vermont Sen. Bernie Sanders told NBC's "Meet the Press" on Sunday that he was thinking of running for president.

Harkin's final steak fry was the largest since Hillary Clinton's last appearance in 2007, when she was joined by Obama, Biden and other Democrats running for president. Bill Clinton has appeared at the event three previous times.

Clinton has said she expects to decide on another campaign early next year.