Ronald Reagan offered a sunny vision for the nation, with a "Morning in America" message that built a GOP brand of optimism and fiscal conservatism. Bill Clinton's "Third Way" helped modernize the Democratic Party brand, casting the party as one that balanced government obligations to needy people with personal responsibility. George H. W. Bush talked about a "kinder, gentler nation," softening any hard edges around the GOP image. And Barack Obama's "Hope and Change" slogan energized young voters wanting something new out of an old political party.

Donald Trump, meanwhile, has been the Republican Party's New Coke, branding experts say. And as with the failed effort to expand the cola's market share, the president is damaging the GOP brand not only to his own political detriment, but to the fortunes of other Republicans nervously eyeing their 2018 re-election campaigns.

Trump is regarded as a master brander in the commercial arena, building real estate and entertainment businesses heavily attached to his name. More like a Martha Stewart than, say, a Kraft Foods, Trump personifies the product he is selling. And when Trump – now suffering from historically low approval ratings in the low-to-mid 30s – struggles, so does the GOP brand he effectively took over when he became the party's presidential nominee and then commander-in-chief, political and branding specialists say.

"When you've got a brand that is tied to a personality, it can be incredibly strong and incredibly vulnerable. It is tied to a human being, and that human being's actions and people's feelings about it, as opposed to the performance of a standardized product or service," says Jason Karpf, a marketing and public relations consultant based in Minnesota. What Trump is attempting now, Karpf says, is what I known in the marketing world as a "brand extension," this one, into the political world. But the effort has been sloppy at best and offensive at worst, experts say, threatening to do serious damage to the GOP brand as a whole.

Recent special and off-year elections are already showing signs of a toxicity that is less Republican-rooted than Trump-specific, according to pollsters and political analysts.

In Virginia, for example, half of voters in Nov. 7's gubernatorial and state legislative elections said Trump was a reason for their vote, and twice as many (34 percent) told exit pollsters they were casting votes to oppose Trump as to support him. Democrat Ralph Northam won the governor's race by nine points, and Democrats made huge gains in the House of Delegates, with recounts set to determine whether the chamber will flip from GOP to Democratic control.

In New Jersey, where Trump has an approval rating of 31 percent, just 11 percent of voters in the state's gubernatorial and local elections said they were voting to show support for Trump. Meanwhile, 29 percent said they were voting to send an anti-Trump message – and Gov.-elect Phil Murphy, a Democrat, won 96 percent of those voters.

Even in deep red Alabama, Trump's tainted brand appeared to have an impact on a special election that led to the upset win of Democrat Doug Jones to replace now-Attorney General Jeff Sessions in the U.S. Senate. Trump initially endorsed interim Sen. Luther Strange, the Republican lost the primary to Roy Moore. And while Moore was surely tainted in his own accord, being accused of preying on teenage girls when he was in his 30s, but Trump's endorsement and robocall of support did not put Moore over the top, even in the heavily Republican state.

In state legislative races, Democrats have flipped 33 contested seats since Trump's inauguration, while the GOP has turned just a single contested seat from blue to red, notes Jessica Post of the Democratic Legislative Campaign Committee. Many of those candidates were inspired by an anti-Trump sentiment.

Trump won the Heart of Dixie with 62 percent of the vote last year, but his approval-disapproval rating in Alabama now is tied at 48 percent apiece. And despite Alabama's reliably red political character, just 42 percent of voters in this week's election said they have a favorable view of the GOP, compared to 52 percent who have an unfavorable view.

And perhaps most troubling for the GOP, there have been ominous signs that suburban voters are moving away from Trump's party. Democrats made big gains in the Nov. 7 county and local elections in the Philadelphia suburbs, especially Delaware County. In Westchester County, New York, north of New York City, Democrat George Latimer, running with an anti-Trump message, unseated two-term GOP county executive Rob Astorino despite being outspent 3:1. Suburban voters helped Democrats pick up seats in the Virginia House of Delegates, including its first two Latinas, both from suburban Prince William County.

Even in Alabama, the surburban shift was felt. In Shelby County, home of the Birmingham suburbs, Moore dropped 7 percentage points from his last statewide election in 2012, going from 63 percent of the vote to 56 percent. While he still won the county, the drop was a significant contributor to his 1.5-point statewide loss.

Those are ominous signs for Republicans, whose party is being branded by an outsider president who prefers provocative remarks about sexual harassment complainants, protesting NFL players and white supremacist demonstrators to the blue-chip GOP agenda of smaller government and lower taxes.

"It shows that a wave is in the works, and if everything continues on this road unabated, you're talking tsunami," says Lee Miringoff, director of the nonpartisan Marist Institute for Public Opinion in Poughkeepsie, NY. "If I was a Republican congressman in a suburban district outside a major metro area, I would distance myself" from Trump, Miringoff says. Not only would a presidential visit and endorsement not be helpful, "it actually could be lethal," he adds.

Trump's own brand could endure, says branding expert Debbie Millman, who teaches at New York City's School of Visual Arts and hosts the podcast "Design Matters." Trump typically blames others when he loses, she notes (Trump, after Moore's loss, said he was right to back Strange first, despite the fact that he also endorsed Moore). "He's able to deflect really well," Millman says. "What is happening, I think, is that people who voted for him were hoping that his brand would reflect on them, and they would get the benefit of his brand, and they are not."

As for Trump's falling poll numbers, Millman says, his hardcore supporters aren't worried or even convinced. "The people that voted for him don't believe or care about those percentages," she says. "Those are people who were being told before the election that Trump had no chance of winning – and he won."

But meanwhile, Republicans lower down the ticket and in party recruitment are scrambling to separate the man heading the party from the ideals of the GOP itself. Republicans have traditionally been committed to getting government out of people's lives, reducing regulation and limiting taxes and spending, notes Emmanuel Wilder, a North Carolina party official active in the Young Republicans National Federation. But the party's brand is being crafted by a man who equated Nazi sympathizers with counter-protesters, he laments, frustrating the GOP's ability to expand its rank and file – let alone elect more Republicans to office.

"It does hurt" party outreach, Wilder says. "I'm an African-American who, when Charlottesville was all happening, thinking, how do I talk about my [conservative] beliefs? How do I talk to my colleagues who are African-American and Asian – how do I have a conversation with them about the comments he's made?

"At the end of the day, there are no good Nazis," Wilder adds, referring to the Charlottesville protesters Trump tacitly defended. "It takes us a step back, and it makes it harder for us to really do the outreach efforts."