2026-05-10T10:00:50.837Z / 美国有线电视新闻网（CNN）
唐纳德·特朗普总统支持率持续暴跌，这加大了2026年中期选举延续21世纪美国政坛最强大趋势之一的可能性。
总统支持率的持续下滑，提高了民主党在11月重夺众议院甚至参议院的概率。
如果民主党拿下任何一个议院，都将继续这场非同寻常的政治动荡：自2000年以来的13次选举中，已有11次出现众议院、参议院或白宫控制权在两党间易手的情况。相比之下，20世纪最后13次选举中，国会参众两院或白宫控制权仅出现5次更迭；若追溯至1960年的最近20次选举，这一数字也仅为7次。
每当选民反对执政党时，政治分析师通常会关注总统及其国会政党的即时决策。但这种快速逆转的模式已根深蒂固，与其说源于战术决策，不如说来自经济、社会和选民群体中没有任何减弱迹象的深层力量。
“再过五六年，如果我们再讨论这个话题，可能会是16次选举中有14次出现选民投票支持变革的情况，”曾为比尔·克林顿担任白宫政治顾问、追踪这一趋势的道格·索斯尼克说道。
这种动荡的部分原因在于，两党但凡掌权，通常仅能以微弱优势胜出。这些较小的优势让执政党几乎没有缓冲空间来承受中期选举的失利——而中期选举失利历来是总统所在政党的常见现象。
“中期选举失利现象并非21世纪才有，但过去执政党通常能消化失利影响并保住多数席位，”斯坦福大学政治学家、保守派胡佛研究所高级研究员布兰迪丝·凯恩斯-罗恩说道。如今，她表示，“多数席位差距极小”，即便小幅逆转也会导致控制权易手。
白宫的“旋转门”现象也体现了类似动态。两党都已稳定拿下选举人团中的大量席位，如今仅需少数摇摆州的小幅 shifts 就能决定选举结果。
但尽管国会和选举人团的微弱差距可以解释权力更迭的频繁发生，这又引出了另一个问题：为何差距会如此微小？
在《身份危机》一书中，加州大学洛杉矶分校政治学家林恩·瓦夫雷克与合著者约翰·赛兹、迈克尔·特瑟勒指出，2016年选举标志着两党间的基本冲突从经济议题转向文化议题的长期趋势达到顶峰。他们写道，在移民、种族多样性和LGBTQ权利等两极分化问题上，特朗普将政治辩论的主轴转向了“关于美国身份与包容性的对立愿景”。
“在我们人生的大部分时间里，政治斗争围绕的是新政议题——即政府的规模和角色，”瓦夫雷克说道。“那些日子早已一去不复返了。我们不再（主要）围绕税率争执。2016年，特朗普提出了这些带有身份认同色彩的议题，而如今……我们争论的是谁配得上成为美国人。”
瓦夫雷克和她的同事认为，建立在这种国家身份对立愿景之上的政治秩序，会让大多数选民更难想象将支持从一个政党转向另一个政党。她说，上世纪90年代初“两党分歧集中在政府角色上”时，更多倾向于某一政党的选民可以想象生活在由另一政党治理的国家“且不会心生反感”。
“那不是一场关乎‘作为美国人意味着什么’的个人化、分裂性的生存危机。所以现在当它变成这样时，选民更难跨越党派界限，”瓦夫雷克说道。
在这些变化之下，政治专业人士基本达成共识：21世纪以来，坚定支持两党任何一方的选民合计占比已增长至约85%甚至略高，这减少了摇摆选民的数量。（在《身份危机》中，作者生动地将此称为美国政治的“僵化”。）
但矛盾的是，牢牢依附于某一政党的大量选民，反而增强了少数不依附选民的影响力。摇摆选民往往是那些相较于两党间的文化和意识形态混战，更看重自身直接经济状况的美国人——而多年来他们对经济状况一直持持续悲观态度。
“最后那15%的选民心怀不满、疏离政治、不参与文化战争，他们几乎都会投票反对执政党，”索斯尼克说道。正如我此前撰文所述，这些心怀不满的选民如今不仅通过换票，还通过是否参与投票来表达不满。
共和党民调专家迈卡·罗伯茨是为CNBC调查经济态度的两党团队成员之一，他表示，未强烈认同任何政党的选民“始终持悲观态度”。
“自2017年以来，没有哪一年独立选民对当前经济状况持乐观态度，”罗伯茨说道。
经济学家和政治策略师一致认为，自上世纪70年代以来收入不平等加剧，许多选民，尤其是未获得大学学位的选民，觉得向上流动比父辈时代困难得多。左翼智库经济政策研究所的乔希·比文斯和两名同事近期测算，如果最顶层的劳动者未占据越来越多的全国总收入份额，普通家庭如今的收入最多可高出3万美元。
“日益加剧的收入不平等是太多美国家庭感到负担能力遥不可及的主要原因，”他们写道。
多年来，工资增长放缓一直令工薪家庭感到沮丧，并加剧了21世纪普遍存在的政治不稳定，多数分析师对此表示认同。但新冠疫情后通胀的急剧飙升将这些担忧推至危机级别。许多家庭如今不再是原地踏步，而是感觉自己正在滑向贫困。罗伯茨表示，尽管失业率和股市等其他经济指标表现积极，但如今“普通美国人唯一关注的经济报告就是加油站广告牌上的油价或购物账单底部的价格”。
这些不满情绪在2024年帮助了特朗普——当时民主党掌控白宫，但如今这种未减的焦虑却成了共和党2026年面临的最大威胁。
“我们已经进入21世纪四分之一世纪，两个政党都没能搞清楚如何满足选民的基本需求，而我们正处于这个新的博弈场中，”瓦夫雷克说道。“这可能就是我余生都要面对的现实。”
总统选举策略的转变也加剧了持续的不稳定。除个别例外情况，2000年以来的总统都将立法议程主要集中在大规模党派法案上——从巴拉克·奥巴马的《平价医疗法案》到特朗普的《宏伟美丽法案》——这些法案通常几乎得不到另一政党的支持，仅通过特殊的和解程序即可通过。
“如今两党在完全掌控政府时，都会利用和解程序强行推进党派议程，”前共和党众议员查理·登特说道，他现在是阿斯彭研究所国会项目执行董事。“这几乎就像是他们已经放弃了通过两党合作通过重大法案的尝试。”
无论这些高度党派化的法案在政策上有何优劣，其政治影响都是引发另一政党的强烈反对。近期的共和党和民主党总统都未采取更渐进的策略，即通过在任期伊始推出有限的两党立法计划来扩大支持基础。即便总统寻求两党妥协——正如拜登在大型基础设施和半导体制造业法案上所做的那样——他们也会发现，自身的党派行动会掩盖这种妥协姿态。
凯恩斯-罗恩指出了新总统如今迅速招致反弹的另一个原因：他们越来越不重视立法，转而通过激进的行政行动推进议程。“当你更多地单方面行事时，很容易做得过火，”她说。
这种持续不稳定的周期在美国政治中并不常见。1840年至1860年内战前的20年里，11次选举中有10次出现了控制权更迭。许多政治分析师认为，1876年至1896年的时期与当下更为相似——11年间有8次选举出现了控制权易手。
和如今一样，19世纪末的这段时期也充满了剧烈变革：从农业经济向工业经济转型、劳资双方的激烈斗争、快速城市化，再加上大规模移民潮。当时和现在一样，许多选民认为两党都无法在动荡中实现经济和社会稳定。
如何才能打破当下的循环？比文斯和索斯尼克一样认为，只有普通家庭的生活水平实现持续改善，政治动荡才可能平息。比文斯指出，一个进退两难的局面是，实施可能带来此类广泛收益的政策，需要某一方掌权的时间比目前看起来更长。
“要做出重大政策改变以摆脱当前的困境……需要一段持续的执政期，而这需要大量民众支持，而在尚未解决问题的情况下，持续获得民众支持难度极大，”比文斯说道。“如何解决这个时机问题是一个真正的难题。”
凯恩斯-罗恩则更为乐观，她认为如果总统采取渐进式策略，以温和的议程逐步争取摇摆选民的支持，就能构建更持久的优势。如果新总统“不过度行事，那么我们将身处一个不同的世界，”她说。“问题在于，一旦上任，你能否约束自己。”
专攻19世纪美国政治的普林斯顿大学历史学家肖恩·威尔entz提出了另一种可能的结局。他指出，一党确立持久优势的稳定时期，几乎总是在一场危机使另一党声名狼藉，并让新总统得以扩大并巩固其联盟之后才到来。
1860年前的动荡时期以亚伯拉罕·林肯和共和党领导联邦在内战中获胜而告终；19世纪末的动荡则在1893年的恐慌削弱了当时掌控华盛顿的民主党后，让共和党得以长期执政。同样，富兰克林·D·罗斯福对大萧条的有力应对，为民主党在华盛顿带来了36年的执政优势。“危机以这样或那样的方式成就了总统，”威尔entz说道。
威尔entz认为，2008年的金融危机同样为民主党提供了重塑政治格局的机会。但他认为，前总统乔治·W·布什和奥巴马都不愿彻底追究华尔街和富豪的责任，这“摧毁了两个政党”，并引发了对“精英”和“被操纵的体系”的广泛民粹主义反弹，助推了茶党、特朗普和伯尼·桑德斯的崛起，并动摇了两个政党的联盟基础。
如今，威尔entz表示，政治体系可能会持续不稳定，直到另一场危机出现，为未来的总统提供另一个构建更持久联盟的机会。“也许这就是我们正在等待的——一场那样的冲击，”威尔entz说道。“如果我赌未来10年，我不会赌它不会发生。”
与此同时，最稳妥的预测是，选民将继续在两党间摇摆，寻求两党似乎都无法提供的答案。
Rapid changes in power have become the new normal in American politics. Here’s why
2026-05-10T10:00:50.837Z / CNN
President Donald Trump’s tumbling approval ratings are raising the odds that the 2026 midterm elections will extend one of the most powerful trends in 21st-century American politics.
The president’s steady decline in popularity has increased the chances that Democrats in November could recapture the House of Representatives, and maybe the Senate too.
If Democrats flip either chamber, it will continue the extraordinary run of volatility that has seen control of the House, the Senate or the White House change hands between the parties in 11 of the 13 elections since 2000. By contrast, control of either congressional chamber or the White House flipped in just five of the final 13 elections of the 20th century and only seven of the last 20 stretching back to 1960.
Each time voters recoil against the party in power, political analysts usually focus on the immediate choices made by the president and his party in Congress. But the pattern of rapid reversals has become so entrenched that it appears driven less by tactical decisions than by deeper forces in the economy, society and the electorate that show no sign of abating.
“Five or six years from now, if we are having this conversation, it will probably be 14 out of 16 elections with people voting for change,” said Doug Sosnik, a former White House political adviser for Bill Clinton, who has tracked the trend**.
Part of the explanation for this volatility is that whenever they do win power, both parties usually have only managed to scratch out small majorities. These smaller majorities leave them with little cushion for the midterm losses that have always been common for the president’s party.
“The midterm loss phenomenon is not new to the 21st century, but often the party in power absorbed the losses” and preserved its majority, said Brandice Canes-Wrone, a Stanford University political scientist and senior fellow at the conservative Hoover Institution. Now, she said, “the majorities are so tight” that even small reversals flip control.
A similar dynamic is evident in the White House’s revolving door. Each party has reliably locked down so much of the Electoral College that small shifts in the handful of swing states now decide elections.
But while narrow congressional and Electoral College margins can explain the frequent shifts in power, that raises another question: What explains the narrow margins?
In their book “Identity Crisis,” UCLA political scientist Lynn Vavreck and co-authors John Sides and Michael Tesler, argued that the 2016 election culminated a long-term shift in the basic conflict between the parties from economic to cultural issues. Around polarizing questions including on immigration, racial diversity and LGBTQ rights, they wrote, Trump tilted the axis of political debate “to competing visions of American identity and inclusiveness.”
“For most of our lifetime, politics was contested over the New Deal issues —the size and role of government,” Vavreck said. “Those days are so gone. We are not (primarily) fighting over the tax rate anymore. In 2016, Trump raised these identity-inflected issues (and) now … we are fighting about who deserves to be an American.”
A political order grounded in such clashing visions of the nation’s identity, Vavreck and her colleagues argued, makes it harder for most voters to envision shifting their support from one party to the other. When “the differences between the parties in the early 1990s” centered on the role of government, more voters who leaned toward one party could imagine living in a country governed by the other “and not hate it,” she said.
“It wasn’t a personal and divisive existential crisis about what it means to be an American. So now that it is, it is harder for voters to make that crossover,” Vavreck said.
Amid these changes, political professionals largely agree that the combined share of the electorate immovably locked down for either party has grown through the 21st century to around 85% or even slightly more, reducing the number of swing voters. (In “Identity Crisis,” the authors memorably called this the “calcification” of American politics.)
Paradoxically though, the large number of voters firmly anchored in either party has increased the clout of the smaller group that is not. Swing voters tend to be the Americans who place less priority on the cultural and ideological firefights between the parties than on their own immediate economic circumstances — about which they have been persistently negative for years.
“That last 15% is dissatisfied, disengaged, not in the cultural wars, and are pretty much voting against whoever is in power,” said Sosnik. Those disaffected voters, as I’ve written, increasingly express their discontent not only by switching their vote, but also by whether they vote at all.
Micah Roberts, a Republican pollster who is part of a bipartisan team that surveys economic attitudes for CNBC, said voters who don’t strongly identify with either party “are consistently pessimistic.”
“There is not a year since 2017 when independents were positive about the current state of the economy,” Roberts said.
Economists and political strategists agree that many voters, especially those without a college degree, feel it has become far more difficult to get ahead than it was for their parents, as income inequality has widened since the 1970s. Josh Bivens and two colleagues at the left-leaning Economic Policy Institute recently calculated that the incomes of average families would be as much $30,000 higher today if workers at the very top had not claimed such a growing share of total national income since then.
“Rising income inequality is the main reason that affordability feels out of reach for too many U.S. families,” they wrote.
The slowdown in wage growth has frustrated working families for years and contributed to the 21st century’s endemic political instability, most analysts agree. But the sharp spike in inflation after Covid-19 raised these concerns to a crisis level. Instead of treading water, many families now feel they are slipping beneath it. Though other economic indicators such as the unemployment rate and stock market are positive, Roberts said, today “the only economic report that ordinary, everyday Americans pay attention to is the price on the gas station billboard or the price at the bottom of their grocery bill.”
Those frustrations boosted Trump in 2024 when Democrats were in the White House, but now that undiminished anxiety looms as the biggest 2026 threat for Republicans.
“We’re a quarter of the way through the 21st century and neither political party has figured out how to satisfy voters’ basics needs while we are playing on this new field,” Vavreck said. “This is where we are going to be probably for the rest of my lifetime.”
Shifts in presidential strategy have also fed the persistent instability. With only occasional exceptions, the presidents since 2000 have centered their legislative agendas primarily on massive partisan bills (from Barack Obama’s Affordable Care Act to Trump’s One Big Beautiful Bill Act) that they typically pass through the special reconciliation process with little, if any, support from the other party.
“Both parties now use the reconciliation process when they have full control of government to jam through their agenda on a partisan basis,” said former Republican Rep. Charlie Dent, now executive director of the Aspen Institute’s congressional program. “It’s almost as if they’ve given up on trying to pass big bipartisan bills.”
Whatever the policy merits of these highly partisan bills, the political impact has been to trigger intense opposition from the other party. Neither recent Republican nor Democratic presidents have followed a more incremental strategy of seeking to broaden their support by starting their terms with limited, bipartisan legislative plans. Even when presidents have pursued bipartisan compromises — as Biden did on his big infrastructure and semiconductor manufacturing bill — they have found that their partisan moves overshadowed that outreach.
Canes-Wrone pointed to another reason why new presidents now stir immediate backlash: They are deemphasizing legislation at all in favor of advancing their agenda through aggressive executive action. “It is very easy when you are operating more unilaterally to overreach,” she said.
Cycles of such sustained instability have been rare in American politics. In the 20 years before the Civil War from 1840 to 1860, ten of eleven elections produced shifts in control. Many political analysts find even more similarities to the period from 1876 to 1896, which saw eight change elections over eleven.
Like today, that late 19th century stretch was defined by wrenching changes — the transition from an agricultural to industrial economy, fierce battles between management and labor, and rapid urbanization, all punctuated by a massive immigration wave. Then, as now, many voters saw the two parties as incapable of delivering economic and social stability amid the tumult.
What could break today’s cycle? Bivens, like Sosnik, believes that politics is unlikely to stop shaking until living standards for average families more steadily improve. The catch-22, Bivens says, is that implementing policies that might generate such broadly based gains will require one side to hold power for a longer stretch than now seems possible.
“In order to make the big policy change to get us out of the trap we’re in … it would require a sustained period of governance, which would require a lot of popular support, and popular support on a sustained basis is really hard when you haven’t solved the problem,” Bivens said. “How to solve that timing problem is a real conundrum.”
Canes-Wrone is more optimistic that a president who focused on incrementally building support with a moderate agenda intended to reassure and gradually solidify swing voters could construct a more lasting advantage. If a new president “didn’t overreach, then we are in a different world,” she said. “The question is whether once you are in office you can restrain yourself.”
Sean Wilentz, a Princeton University historian who specializes in 19th-century US politics, points toward a different possible endpoint. The eras of stability when one party established a lasting advantage over the other, he noted, have almost always come after a crisis that discredited the other side and allowed a new president to expand and solidify his coalition.
The period of turbulence before 1860 ended when Abraham Lincoln and Republicans led the Union to victory in the Civil War; the late 19th-century upheaval gave way to sustained Republican dominance after the panic of 1893 undercut the Democrats then controlling Washington. Similarly, Franklin D. Roosevelt’s vigorous response to the Depression powered 36 years of Democratic advantage in Washington. “Crises help make presidents one way or another,” Wilentz said.
The financial crisis of 2008, Wilentz believes, similarly offered Democrats a chance to reorder politics. But, he argued, the reluctance of first George W. Bush and then Obama to hold Wall Street and the wealthy fully accountable “blew up both parties” and ignited the free-floating populist backlash against “elites” and a “rigged system” that elevated the tea party, Trump and Bernie Sanders — and has unsettled both coalitions.
Now, Wilentz says, the political system may remain unstable until another crisis emerges that provides a future president another chance to build a more durable coalition. “Maybe that’s what we are waiting for — a shock like that,” Wilentz said. “If I was betting about the next 10 years, I wouldn’t bet against it.”
In the meantime, the safest bet is that voters will continue ricocheting between the parties, searching for answers neither seems able to provide.