updated 2:30pm ET
(CNN) - Bill Clinton's back on the trail.
As he's done the past couple of election cycles, the former President's helping fellow Democrats. But this time around, his campaigning comes with the prospect of his wife making a second bid for the White House in 2016.
First stop for Clinton, who's arguably his party's biggest rock star on the campaign trail, was Tuesday in Louisville to help Kentucky Secretary of State Alison Lundergan Grimes, the Democratic challenger to Senate Minority Leader Mitch McConnell. The top Senate Republican is running this year for a sixth term.
Clinton has been a tireless campaigner in recent years, and he was the highest of high-profile surrogates for President Barack Obama in the 2012 election. He gave an impassioned nominating speech for the President at the party's national convention in Charlotte.
Clinton often stumps for fellow Democrats in red or purple states, such as Kentucky, where Obama is not very popular.
"President Clinton has the unique ability to travel to red states to reach Reagan Democrats that most Democratic surrogates do not," Democratic strategist Ben LaBolt told CNN.
"Kentucky has more registered Democrats than Republicans, but they often split their ticket between state and federal candidates. President Clinton could help tip the scales," added LaBolt, who worked for Obama from his Senate years through 2012 and served as national press secretary for his re-election campaign.
The Clintons have a strong track record in Kentucky. Bill Clinton carried the state in his 1992 presidential election and his 1996 re-election, and Hillary Clinton did extremely well there, winning the 2008 Kentucky Democratic primary in a landslide over Obama.
"I love Kentucky. You’ve been good to me. You voted for me twice. You have been great to Hillary. I love Kentucky," Clinton told the audience, which the Grimes campaign estimated at over 1,200 people.
"Bill Clinton resonates here. He knows how to talk to people here, being from Arkansas, in a way that a lot of other national politicians do not," said a top Kentucky Democrat, who asked to remain anonymous to speak more openly. "I would imagine we'll see plenty of the former President here in Kentucky this year."
Poll numbers that pop
He also remains popular with Americans.
Clinton's favorable rating stood at 71% in a Fox News poll conducted last April. Ninety-four percent of Democrats and two-thirds of independents questioned in that survey said they had a positive view of Clinton, with Republicans divided. And his favorable rating stood in the upper 60's in CNN/ORC International, CBS News/New York Times, and Gallup polls conducted during the 2012 election year.
Paul Begala, a senior political adviser in the Clinton White House and a CNN contributor, said he suspects Clinton's in such demand because "he is beloved by Democrats, admired by Independents and respected by Republicans."
And Maria Cardona, another CNN contributor and veteran of the Clinton administration, said the former President "can mobilize the base, the Democratic coalition, as well as independent voters. And as a son of the South, he can come 'home' and credibly speak to voters in Kentucky in a way that President Obama can't."
A senior Democratic Senate source agrees, telling CNN that Clinton's "one of our best surrogates in purple and red states."
That may make Clinton a busy man this year. Democrats hold a 55-45 majority in the Senate (53 Democrats and two independents who caucus with the party), but are defending 21 of the 36 seats up for grabs in November's midterm elections. And half of the seats the Democrats are defending are located in red or purple states.
On the eve of Clinton's visit to Kentucky, McConnell's campaign sent an email to reporters trying to deflate the Clinton image, pointing out that the former president's track record as a surrogate in the state has not been very successful in recent years.
There was a similar message from McConnell on Tuesday, as he spoke to reporters on Capitol Hill.
"In 2008 both Bill and Hillary Clinton came to town including the day before the election and I won by a 100,000 votes. So I welcome President Clinton back to Kentucky. Every time he has come it has been really good for me," the minority leader said.
And a trio of Republican strategists CNN spoke with agreed.
"Bill Clinton isn't as toxic as President Obama is in Kentucky, but he still won't be much of an asset to Grimes, said CNN contributor Kevin Madden, a senior adviser on Mitt Romney's 2008 and 2012 campaigns. "Clinton hasn't been helpful to Democrats there in the past. Bruce Lunsford lost handily in 2008, as did Jack Conway in the 2010 cycle, with nothing to show for Clinton's help."
"President Clinton has been to Kentucky nearly every cycle to promote his favored candidate and every cycle that candidate has lost resoundingly," agreed GOP strategist Brian Walsh, who served as communications director for the National Republican Senatorial Committee the past two election cycles.
"The Democrats using Bill Clinton to visit states like Kentucky only accentuates Barack Obama's toxicity. There's no doubt Bill Clinton will offer an outstanding stump speech. However, a controversial political figure from the past offering a few well-packaged words will not cause Kentuckians to forget how horrible Barack Obama's policies are making their lives right now," added Hogan Gidley, a Republican strategist who worked as a top aide to then-Arkansas Gov. Mike Huckabee, served as executive director of the South Carolina Republican Party, and was a senior adviser on Rick Santorum's 2012 White House bid.
Grimes is the daughter of a former Kentucky Democratic Party chairman who has long ties to Clinton. Jerry Lundergan was a major supporter of Clinton in both his presidential election victories and chaired Hillary Clinton's 2008 campaign in Kentucky.
One thing that many of the candidates Bill Clinton's personally helped on the campaign trail the past couple of cycles have in common is that they backed his wife's 2008 White House bid.
But those with ties to the Clintons dismiss the notion that Bill Clinton's 2014 campaign moves are all about helping his wife if she runs in 2016.
"I think it's inaccurate to analyze his 2104 campaign schedule merely through the prism of 2016. President Clinton believes that campaigns matter because ideas matter, and wherever someone is running on the ideas he championed in the White House, he's going to want to campaign for them," said Begala, a senior adviser for Priorities USA, the super PAC set up to support Obama's 2012 re-election that's now raising money for a potential Clinton campaign.
"Everything the Clintons do from here on out will be perceived by as self-serving by some. As such, the same will be read into President Clinton helping fellow Democrats in 2014," admitted Cardona, before listing three reasons why this isn't the case in 2014.
But she added that "the fact that it (Bill Clinton's 2014 campaign efforts) could ultimately help his wife if she runs, is a very nice added bonus."
CNN's Gabriella Schwarz contributed to this report