RISON, Ark. — Bill Clinton is coming to Arkansas to appear at four rallies for the campaign of endangered Democratic Sen. Mark Pryor. Democrats hope Clinton's visit will change the dynamics of a race in which Pryor has trailed Republican challenger Rep. Tom Cotton in eight of the last ten polls, going back to the summer. After all, Clinton remains a huge presence here in Arkansas; even though he lives on the global stage, he's never really left this state, not just with his visits, but the Clinton Library, the 2012 re-naming of Little Rock National Airport to Bill and Hillary Clinton National Airport, and evidence everywhere of his 12 years as governor and eight as president. Clinton put Arkansas on the map, and everybody knows that.

But the Clinton factor in today's Arkansas Senate race may be difficult to calculate. Of course Clinton will attack Cotton on the stump, but Cotton is appealing to lots of Arkansans who once voted for Clinton, either as governor, or president, or both. To some of those voters, there's a certain continuity between supporting the moderate Democrat Bill Clinton, beginning when he was first elected governor in 1978, and supporting Cotton today. In a state that has rapidly switched from blue to red, they believe they have stayed the same, while the Democratic Party has changed. So for a young, ambitious Republican politician, it might not be a good idea to attack the man so many Republican voters once supported. And indeed, in an interview on his campaign RV as it bounced along the bumpy roads of rural Arkansas, Cotton not only refrained from attacking Clinton, he went out of his way to compare Clinton's legacy favorably to the record of President Obama.

It began when I asked Cotton what accounts for Clinton's beloved elder statesman status among many Americans, given the facts and the legacy of Clinton's scandal-plagued time in the White House. "The facts and the Clinton legacy look a lot better in contrast to the Obama legacy," Cotton replied. "I'm not concerned about Bill Clinton's support for Mark Pryor. I'm worried about Mark Pryor's support for Barack Obama."

At that point, Cotton went on at some length to compare the two Democratic presidents, one good, one bad:

They faced very similar political circumstances in their second year in office. They lost the Congress because of unpopular policies, and they took very different paths. Barack Obama moved even further left and secured nothing but a hollow re-election, without any lasting legacy or accomplishment. Bill Clinton worked with a Republican Congress. They certainly had their differences on many issues, but look at what they also accomplished. Welfare reform that was maybe the most significant social policy achievement in two generations. Tax cuts that helped increase the economy, as they typically do. Getting the budget back in balance for the first time in decades, as well. When you compare that to Barack Obama's tenure of trillion-dollar deficits and continued left-wing speechmaking, as opposed to working with the Congress that represents the American people, it's not surprising that more people have a favorable opinion of Bill Clinton as compared to Barack Obama.

What about Clinton's impeachment, I asked, as well as his reputation for dishonesty? "I'm not going to re-litigate things that happened when I was a college student," the 37 year-old Cotton said. "I just think that [Clinton's] record of governing, from a policy standpoint, and the effect that it had on the lives of Arkansans, is clearly superior to what Barack Obama has done. And if Mark Pryor had stood up more to the Obama agenda, then Mark Pryor wouldn't be about to lose re-election."

Cotton's assessment of Clinton tracks closely with the opinions of some of the Cotton supporters — former Democrats — who came to see him at a campaign stop in Rison, a town of 1,344 in Cleveland County in southeastern Arkansas. "I voted for Clinton as governor and president," said Hardy Herrington, who with his wife Tabitha was among the 60 or so who came to see Cotton at a small park on Main Street. "Of course, Clinton dabbled in the left, but he had enough sense to come back to the center and won a second term."

"I've always voted Republican, except I did vote for Clinton as president," Tabitha Herrington added. When I asked whether she had voted for Clinton for governor as well, she answered, "Oh, yes."

Hardy went on to say that after Clinton left office, his party changed. "When the Democratic Party made a sharp turn to the left, they left me behind," he said. "I didn't leave them. They left me. They just no longer support the values that I cherish."

Now, the Herringtons are big Tom Cotton fans. After the candidate gave a brief talk, other former Democrats in the Rison crowd explained their migration from the Democratic Party to the GOP.

"I grew up a Democrat, because folks were Democrats," said Larry King, a former local school board member.

"We all were, in this county," added King's friend Tom Taylor, who was a county judge for a while in the 1980s. "That's back when Democrats were Democrats."

Taylor thought for a moment. There were a few exceptions, he said, even a long time ago. "Well, there was -- " Taylor explained, naming a couple of Rison residents.

"They were die-hard Republicans," said King.

"And they were right," said Taylor. "And we all thought they were a little different."

Taylor said he began to evolve philosophically many years ago, but even then had to live in the Arkansas Democratic system. "I changed back in the 1970s," he said. "But I ran as a Democrat in 1980, because in this county you either ran as a Democrat or you didn't get elected."

"People voted for the party instead of the man," King added.

Now that system has changed dramatically. In the course of just a few years, the Democratic Party in Arkansas, which stayed in power far longer than in other southern states, has almost collapsed. (For a good look at the change, see Fred Barnes' recent piece in The Weekly Standard.) Tom Cotton is riding on, and also creating, a new wave of Republican strength.

But the past is still around in the person of Bill Clinton, still a major figure in Arkansas politics, still the Democrat many of today's Arkansas Republicans supported. For Cotton, whose parents long voted Democratic, Clinton was the important man he would see at various fairs and festivals during his childhood. "We have lots of pictures of our family with him at those events," Cotton said during our RV interview. "I vaguely remember being around him." (Cotton has never sat down for a talk with the former president as an adult.)

Now, Clinton promises to be a factor, although it's not clear how strong a factor, in the closing days of the Senate race. When I noted that Clinton is going to attack him pretty frequently as Election Day approaches, Cotton showed no concern. "We're in the height of a political campaign," he answered, adding that Clinton attacked the current Arkansas Republican senator, John Boozman, when Boozman successfully ran for office four years ago. "He's going to say what Democrats always say about Republicans in campaigns," Cotton added dismissively.

But Cotton doesn't seem inclined to fire back; instead, he had only nice things to say about Clinton. The way Cotton sees it, no matter what Bill Clinton does or doesn't do, this race is about the current president, not the past one. And also — lest anyone forget — about Mark Pryor. "Barack Obama said it's his policies that are on the ballot," Cotton said. "I agree for once with Barack Obama. His policies are on the ballot, as is Mark Pryor's support for them."