– Al Franken’s friendship with Hillary Clinton started 22 years ago with a joke the two exchanged at a White House dinner.

Their bond deepened in 2008, when Franken battled in the closing days of a high-stakes Senate race that appeared to be slipping away. Clinton, who was a busy surrogate for Barack Obama that fall, flew to Minnesota twice in the last two weeks to campaign for Franken in the Twin Cities and Duluth.

“Believe me, when you win by 312 votes,” Franken said, “you remember these things.”

Now he is trying to pay her back. The former "Saturday Night Live" star has visited nine states this year in an all-out effort to help Clinton get elected, raising money and campaigning in places like New Hampshire, Wisconsin and Los Angeles.

Franken’s loyalty to Clinton and their shared passion for policy is giving rise to speculation that he could be selected for a Cabinet post or take on a new, higher-profile role in the Senate as a key ally of the new president.

“The Clintons have long memories,” said Ken Martin, state DFL chairman and a personal friend of Hillary Clinton. “It would not surprise anyone if Al Franken would be considered for any sort of post in the administration.”

Franken’s pace is likely to intensify as the election season heads into its critical final weeks: His schedule is packed with travel from coast to coast.

“Senator Franken is one of this campaign’s most effective advocates,” said Clinton campaign spokesman Brian Fallon.

Franken first met Hillary and Bill Clinton in 1993 at an ideas festival in South Carolina.

Then a comedy writer on Saturday Night Live, Franken was asked to help write a skit that poked fun at the famous “Harry and Louise” ad campaign. The commercials, which ran between 1993 and 1994, portrayed a regular American couple, Harry and Louise, sitting at their kitchen table discussing Clintons’ health care reform plan. The ads, paid for by the health insurance industry, talked about how bureaucrats in Washington were going to take over health care and leave Americans with few options.

Franken wrote a fake commercial for the journalism Gridiron Dinner that cast the Clintons as Harry and Louise, paid for by “the Coalition to Scare Your Pants Off.” The skit got rave reviews.

Hillary Clinton invited Franken to dinner at the White House in 1994 for a movie screening on a Friday night. Franken was deep in SNL writing and said he felt a “patriotic duty” to accept the invitation. But he had to ask his boss, Lorne Michaels, for the night off.

“I said to her, ‘I gotta check with Lorne because we have a show the next night and Friday nights are kind of important,’ ” said Franken, who recalls that Clinton was amused at the dilemma. “So when I came to the thing, the dinner, when I show up, she goes like, ‘So you checked with Lorne?’ and I said ‘Yeah, he said it was OK,’ and she said, ‘Did he dock you?’ ”

“She is funny,” Franken said.

The two stayed in touch while she was in the U.S. Senate, representing New York. He interviewed her on his “Air America” radio show during the Democratic National Convention in 2004 and dined with her occasionally.

They discovered a shared passion for issues and a similar outlook on problems facing the world.

“Senator Franken is thoughtful and loves thinking through policies and loves having those deep conversations about what we need to do,” said Stephanie Schriock, Franken’s former campaign manager and now president of EMILY’s List, an organization that seeks to elect pro-abortion rights women to office. “And Hillary is like that, too … They come at it from the same point of view.”

Franken gave an example.

“We will talk about health care delivery reform. … When you start getting into the weeds with delivery reform, she’s happy,” he said. “I think she’s more comfortable doing the work than she is in the campaign part.”

Franken’s bid for the U.S. Senate in 2008 came at a critical time in Clinton’s first presidential run. She didn’t ask Franken for help, he says, because she knew that would have put him in a tough spot. He was vying for the DFL endorsement as party activists were sharply divided between Clinton and Barack Obama. Franken ultimately endorsed Obama after he emerged as the nominee.

Franken’s run against incumbent Republican Sen. Norm Coleman remained close throughout the fall. Coleman was pounding Franken for his provocative past as a humor writer and comedian, including a satirical column he wrote for Playboy magazine in 2000 called “Porn-O-Rama” where he would visit a fictitious “sex institute” to take part in sexual acts with robots and humans. Franken’s past was hurting him in the state’s more conservative areas and among women.

Clinton’s help came at a critical time, said Dan Cramer, a Franken consultant at the time.

Cramer said he was immediately struck by Clinton’s tireless effort to aid Franken. Usually, a top-level surrogate like that will land in a city, do a quick event and move on to the next state.

Clinton made two critical stops in Minnesota, without hesitation. “Hillary just said, ‘Yes,’ ” Cramer said.

In both instances, Clinton assured activists that the former comedian was a very serious candidate and he’d be a really good senator.

“I think that’s a lot of what people wanted to hear to throw themselves into it the final three weeks,” Cramer said.

After Franken was sworn into the U.S. Senate, he stayed in close contact with Clinton, who was then secretary of State. He called her directly to talk about Al-Shabab, the terrorist organization based in Somalia, and for help with Minnesota hitchhikers who were detained in Iran. The hitchhikers were later freed.

The alliance between Franken and Clinton is likely to get a new test if she wins the election.

Even if Franken stays in the Senate, he could become a critical Clinton ally. On the campaign trail, Franken usually squeezes in an event for Democratic Senate candidates, potentially building a coalition of allies.

Franken, who has two new grandchildren, shrugs off the long hours on planes to help his longtime friend. He talks about how she will work on climate change, mental health and education reform — issues that are all passions of his, as well.

“She is in my mind the smartest, hardest working, toughest, most experienced person in the world for this job,” Franken said.