When it comes to political family rivalries, the one between the Beshears and the Lundergans in Kentucky has to rank near the top of the list.

It's a decades-old story with roots in state legislative campaigns that involves two generations of Democratic politicians who have clashed at key junctures and may well lock horns again.

For now, the dynamic looks pretty friendly. Gov. Steve Beshear (D) voiced his support Tuesday for Secretary of State Alison Lundergan Grimes (D), who is challenging Senate Minority Leader Mitch McConnell (R).

"I’m going to support Alison Lundergan Grimes for the U.S. Senate in every way that I can, and whatever they want me to do, I’m going to be there to do,” Beshear told reporters.

Striking words, since Beshear has a rocky history with Grimes's father, former state Democratic Party chairman Jerry Lundergan. The rift dates back to the 1970s.

"I really can't speak to what personal relationship they've had, but by reputation they don't like each other," said veteran political observer Al Cross, a former Louisville Courier-Journal political writer. "They are clearly cut from different cloths and move in different circles."

Beshear, a Kentucky native, moved to New York shortly after graduating from law school. He soon returned to the Bluegrass State and won a state House seat in 1973. In 1975 and 1977, he faced a challenge in the Democratic primary from Lundergan. Beshear won both showdowns, and went on to be elected attorney general in 1979. That same year, Lundergan was elected to Beshear's seat.

Years later, the two Democrats clashed again. Beshear, then lieutenant governor, ran for governor in 1987. Lundergan backed one of Beshear's opponents, Wallace Wilkinson, who went on to win the governorship.

In 2011, Beshear appointed Bowling Green Mayor Elaine Walker to fill an open secretary of state seat, instead of appointing Grimes, then an attorney, a move which would have been seen as an effort to mend ties between the two sides. Grimes decided to run against Walker and defeated her later that year.

"We had a family feud and Alison won the family feud," said veteran Democratic strategist Dale Emmons, a close friend of the Lundergan family who worked on Grimes's 2011 campaign.

Grimes announced her Senate campaign last week. Her rocky rollout has prompted questions about her preparedness to run against McConnell. But it's clear that she is the best candidate Democrats could have recruited for the race.

Beshear said he wasn't given a heads-up that Grimes was going to run, but had pledged to support her in advance. Grimes spokesman Jonathan Hurst told the Louisville Courier-Journal there was no effort to keep Beshear out of the loop.

Emmons said he thinks the tension between the two sides has been overstated. But he acknowledged that the rift has been real and likened the dynamic to a college sports rivalry.

"I would equate it to basketball," he said. "In Kentucky we have two competitive basketball programs. We have some Louisville fans and some University of Kentucky fans, but we all are Kentucky teams."

In other words, both sides are loyal to the Democratic Party, which badly wants to defeat McConnell. That could be enough to spur a harmonious effort in 2014. And Beshear's 1996 loss to McConnell may even be an added incentive to boost Grimes as much as possible, said one Kentucky Democrat.

"He has a score to settle," said Danny Briscoe, a veteran Democratic operative who worked on Wilkinson's 1987 campaign. "He ran against McConnell and lost."

Beshear's office referred questions about his relationship with Lundergan to the state Democratic Party. "As the Governor said yesterday, these two men ran against each other a very long time ago, and the Governor has no hard feelings at all," said Democratic Party Chairman Dan Logsdon. "He thinks Alison will be a strong candidate, and he is excited to help her in every way he can."

There is one more variable in the story: the 2015 attorney general's race. Beshear's son Andy Beshear is weighing a bid. Grimes had also been looking at the race before she opted for a Senate run. But if she loses in 2014, running for attorney general wouldn't be out of the question the following year.

It's safe to say we haven't heard the last of this rivalry just yet.