Party membership trends give Republicans no reason to celebrate, with Democrats widening their numerical rank-and-file advantage over a GOP struggling to find its footing after losing the presidency and both chambers of Congress in November, according to a Gallup poll released Wednesday.The poll found that nearly half – 49% – of Americans identify as Democrats or independents leaning toward Democrats, while a combined 40% are Republican or GOP-leaning. That first-quarter 2021 advantage is the biggest since the fourth quarter of 2012, during which President Barack Obama won his second presidential election. Without including independents leaning one way or the other, Republicans fared worse, with 25% of the public calling themselves members of the GOP, just a few percentage points higher from Gallup polling's all-time low of 22% in 2013. Gallup found that 30% of Americans identify strictly as Democrats.The numbers align with trends Republicans saw after the failed insurrection at the U.S. Capitol Jan. 6, with tens of thousands of Republicans, many in battleground states, switching their party registrations to independent or Democrat."Their support is kind of disappearing. They're hemorrhaging supporters," says Gallup senior editor Jeff Jones. The party has a long time to recover and woo back rank-and-file members before the 2022 midterms, Jones says, noting that midterms in a president's first term tend to favor the party out of power.But this cycle, the math is more complicated for Republicans, experts say. Former President Donald Trump remains a polarizing figure overall but is causing fissures within the GOP as well – and at a time when Republicans need to band together if they want to win elections.In the aftermath of the Capitol riots, many Republicans took the extraordinary step of changing their party registrations, a dramatic move, considering there was no upcoming election that spurred the actions."This is absolutely something they wanted to do to make a personal statement about which party they belonged to" – and it wasn't the GOP, says University of Florida political science professor Michael McDonald, who tallies registration and voter trends through his nonpartisan United States Elections Project."What was happening in mid-January was probably already happening" to the party. It's just that people were not taking the affirmative step of actually changing their registrations from GOP to Democrat or independent, McDonald says. "This survey is confirming … a broader movement."An analysis of voter rolls by Colorado Public Radio, for example, found that about 4,600 Republicans changed their party status in the week January 6-12, without similar trends for other parties. Other news organizations found flips from GOP registration in other states – at least 6,000 in North Carolina, 10,000 in Pennsylvania and 5,000 in Arizona.That doesn't mean those voters will reject GOP candidates at the polls, let alone cast ballots for Democrats. But given the close margins in those states, bringing even a few thousand voters over to another political team could be critical in future elections."Obviously, for most people, party registration is purely symbolic," unless party membership is required to vote in a primary, says Ryan Winger, director of data analysis and campaign strategy at Denver-based Magellan Strategies, a firm that serves Republican candidates. As of 2018, Colorado does not require people to be registered in a party to vote in a primary."But I would say any time you're losing registrants, it's a concern," Winger adds. "For all the people who took that step, there's a lot of people who came close to doing it, I'm sure."The party flips may well have been a one-time reaction to the dramatic events of Jan. 6, some Republicans say. In Arizona, for example, media reports found that some 10,000 GOPers had switched their party registrations, notes Republcian consultant Chuck Coughlin, president of the Phoenix-based consulting firm HighGround.But in March, Coughlin says, citing state elections data, the numbers were more similar, with 2,272 GOPers and 2,174 Democrats changing their registrations. President Joe Biden won Arizona's 11 Electoral College votes by 10,457 votes, or 0.3% of the vote in the Grand Canyon State. Winger and others say Trump is a double-edged sword for the party. The former president brought in a lot of new voters with his brash manner and populist approach. Candidates who continue to embrace Trump may keep those voters motivated – but it will still be harder, without Trump on TV and Twitter every day.But if GOP candidates try to appeal to those GOPers who have ejected Trump – especially those who drew the line at the January insurrection and change their registration – they risk alienating Trump loyalists, Winger says."It is concerning, and it's something the party is going to have to really reckon with. There's a chance for them to do that in primary elections" in upcoming elections, he adds.Both parties, however, face a public relations problem with voters, Jones notes. Witout "leaners," those describing themselves as independent comprise 44% of the electorate, up from 38% in the last quarter of 2020, according to the Gallup study."It's definitely a trend," Jones says. As recently as 15 years ago, people had a generally positive view of both parties; "now, it's rare for a party to have a positive view (among voters), let alone both parties," Jones adds. He poses two competing explanations – that people are tired of hyperpartisanship and don't want to be part of it or that the parties themselves are unwelcoming to those who do not agree with the entire party platform.Democrats have a historical disadvantage, since the minority party tends to pick up seats in a mid-term, and Biden – like his most recent Democratic predecessor, Barack Obama – could be branded as overreaching, with his massive, $1.9 trillion coronavirus relief package already enacted and his proposed $2.25 trillion infrastructure plan.Biden's advantage is that the GOP is fractured, and the Democratic spending plans – unlike the Affordable Care Act, which Obama passed early in his first term – are popular with voters. And if the economy continues to grow while vaccine distribution hums along, the incumbent will benefit.Things are "probably working in the Democrats' favor. But two years is a long time," Jones says.