About 500 Democrats gathered in Des Moines tonight to honor retiring U.S. Senator Tom Harkin. Iowa Democratic Party chairman Scott Brennan, a former member of Harkin’s senate staff, called it a “bittersweet” event.

“We don’t have the hall reserved long enough for all the tales we need to tell,” Brennan said.

Harkin, who announced in January of 2013 that he would not seek reelection this year, was inducted into the Iowa Democratic Party’s “Hall of Fame.”

“I don’t stand on the shoulders of giants,” Harkin said. “I stand on the shoulders of ordinary Iowans who put their trust in me, worked their hearts out for me, stood by me when the going got tough.”

AUDIO of speeches by Ruth and Tom Harkin, 30:00

Harkin reminisced about his political mentors and his nearly 40 years of service in congress, then concluded by saying it’s time to pass the torch to a new generation.

“I may be retiring from the senate, but I am not retiring from this fight,” Harkin said. “…As long as I have a breath, I want to be part of that effort.”

President Obama as well as possible 2016 presidential candidates Joe Biden and Hillary Clinton were among those who recorded video messages that were played at the event.

“I’m getting ready to take a momentous plunge and you are uniquely suited to help me,” Clinton said in her recorded message.

“It’s a new adventure full of excitement, but also responsibility and unexpected challenges. I could really use you in my corner. No one knows the terrain better, so Tom I need to ask — what’s the secret to being such a terrific grandparent?”

Congressman Bruce Braley is the Democratic candidate who is seeking Harkin’s seat and Braley called Harkin a friend and mentor.

“For the last 40 years, Tom, you have shown all of us in this room what it means to be a Democrat,” Braley said.

Congressman Dave Loebsack, a Democrat from Iowa City, called Harkin his hero.

“And he’ll continue to be my political hero so long as I have a breath in my body,” Loebsack said. “Thank you, Tom. Thank you for everything.”

Jack Hatch, the Democrat who’s running for governor this year, is also among the ranks of former Harkin staffers or “Harkinistas” as they call themselves.

“Anybody who has worked on a Harkin campaign, will you stand up? How about anybody who went to New Hampshire for Tom Harkin — can you stand up? And anybody who’s voted for Tom Harkin, can you stand up?” Hatch said and, as the entire crowd stood applauding and cheering, Hatch concluded with this: “Tom Harkin, this is your life.”

Harkin, who ran for president in 1992, hosts an annual steak fry fundraiser every fall. Keynote speakers at the event like Al Gore and Barack Obama went on to win the Iowa Caucuses. In 2012 Maryland Governor Martin O’Malley was the keynote speaker at the Harkin Steak Fry and O’Malley returned to Iowa tonight to pay tribute to Harkin.

“Health care for all, that would not have happened without his voice and his strength of service,” O’Malley said during a brief, five minute speech.

Harkin was first elected to the U.S. House in 1974. Harkin won a seat in the U.S. Senate in 1984 and won re-election four times. Harkin will speak again Saturday at the Iowa Democratic Party’s state convention. Delegates will formally nominate Monica Vernon for lieutenant governor. Vernon is the Cedar Rapids City Councilwoman Jack Hatch — the Democratic Party’s nominee for governor — has chosen as his running mate.