Who will control the next Congress?

The new president is much less likely than usual to see allies take charge on Capitol Hill

新总统在国会山掌权的可能性比平时小得多

10月 10日, 2024 08:23 上午

AMERICANS ARE fixated on whether Kamala Harris or Donald Trump will win the presidency on November 5th. But what the victor will actually be able to achieve depends in large part on which party controls Congress. Most new presidents have long coattails: not since George H.W. Bush was inaugurated in 1989 has one taken office without his party also controlling both chambers of Congress. But this year the race for congressional control looks as close as the presidential one, putting the normal outcome in doubt. If the election of 2024 is as much of a nail-biter as expected, the prospect of divided government—and with it the shelving of much of the new president’s agenda—looms large.

答：美国人关注卡马拉·哈里斯或唐纳德·特朗普是否会在 11 月 5 日赢得总统大选。但胜利者实际上能够实现什么目标，在很大程度上取决于哪个政党控制国会。大多数新总统都有很长的马尾辫：自1989年乔治·赫伯特·沃克·布什（George H.W. Bush）就职以来，还没有一位总统的政党同时控制国会两院。但今年，国会控制权的竞争看起来与总统的竞争一样接近，这使得正常结果受到质疑。如果说 2024 年的选举像预期的那样激烈，那么政府分裂的前景——以及随之而来的新总统大部分议程的搁置——就迫在眉睫。

This week we launched The Economist’s forecast of the congressional elections, to complement our presidential-election model, which we first published in June and currently gives Ms Harris a 51% chance of victory. It finds that, taken individually, each chamber is more likely than not to see a change in partisan control. The Republicans’ chance of flipping the Senate is 66% and the Democrats’ of winning the House of Representatives is 61%.

本周，我们推出了《经济学人》对国会选举的预测，以补充我们在 6 月首次发布的总统选举模型，该模型目前认为哈里斯女士获胜的机会为 51%。研究发现，单独来看，每个参众两院都更有可能看到党派控制的变化。共和党翻转参议院的几率是 66%，民主党赢得众议院的几率是 61%。

However, this does not mean that the two parties are likely simply to trade places on Capitol Hill. If Republicans do manage to win the Senate, their House candidates will probably exceed expectations as well, and vice versa. After accounting for these correlations, our model finds that the two most probable outcomes remain the typical presidency-House-Senate “trifecta” for either Republicans or Democrats, with both parties having around a one-in-four shot of securing one. The next-likeliest scenarios are those with a Republican Senate and a Democratic House, either during a Harris presidency (a 16% chance) or a Trump one (15%) (see chart).

然而，这并不意味着两党可能会简单地在国会山交换位置。如果共和党人真的成功赢得参议院，他们的众议院候选人也可能超出预期，反之亦然。在考虑了这些相关性之后，我们的模型发现，共和党或民主党最有可能的两种结果仍然是典型的总统-众议院-参议院“三重奏”，两党都有大约四分之一的机会获得一个。下一个最有可能的情况是共和党参议院和民主党众议院的情况，要么是在哈里斯担任总统期间（16% 的机会）还是在特朗普担任总统期间（15%）（见图表）。

Chamber musing
密室沉思

The model’s most eye-catching result is probably the relatively high chance it gives the Democrats of hanging on to the Senate, given the difficult races several of their incumbents face. The party holds 51 of the 100 seats (counting four supportive independents), but is guaranteed to lose one owing to the looming retirement of Joe Manchin, a Democrat-turned-independent from heavily Republican West Virginia. As a result, it cannot afford to lose any more seats—or the presidency, since the vice-president is the tie-breaker if the chamber is evenly divided. Of the 34 Senate seats up for grabs this year, 23 are held by Democrats.

该模型最引人注目的结果可能是，考虑到民主党的几位现任议员面临的艰难竞争，它让民主党保住参议院的可能性相对较高。该党拥有 100 个席位中的 51 个（包括 4 个支持独立的独立人士），但由于乔·曼钦 （Joe Manchin） 即将退休，他是一名来自共和党占主导地位的西弗吉尼亚州的民主党人，后来成为独立人士。因此，它不能再失去任何席位或总统职位，因为如果参议院平分秋色，副总统就是决胜局。在今年争夺的 34 个参议院席位中，有 23 个由民主党人占据。

乔.曼钦 图源:britannica.com

Three factors account for the model’s insistence that Democrats have a plausible path to victory in the upper chamber. One is that the party’s candidates in many races expected to be competitive—including those in places where Mr Trump and Ms Harris are neck-and-neck, such as Arizona, Michigan, Nevada, Pennsylvania and Wisconsin—enjoy surprisingly large leads in polls. If Democrats do well enough overall that Ms Harris and the two Democratic incumbents seeking re-election in red states (Jon Tester of Montana and Sherrod Brown of Ohio) all win, the party holds on in the Senate 89% of the time.

该模型坚持认为民主党在参议院获胜的道路上似乎是合理的，有三个因素。一是该党候选人在许多预计会具有竞争力的竞选中——包括那些在特朗普和哈里斯势均力敌的地方，如亚利桑那州、密歇根州、内华达州、宾夕法尼亚州和威斯康星州——在民调中取得了惊人的巨大领先优势。如果民主党的总体表现足够好，以至于哈里斯和两位寻求在红州连任的民主党现任议员（蒙大拿州的乔恩·泰斯特（Jon Tester）和俄亥俄州的谢罗德·布朗（Sherrod Brown））都获胜，那么该党在参议院的保住率将达到89%。

The second reason the Democrats may hold the Senate is that the model is not yet ready to write off Mr Tester. Although recent polls have put him down by 6-8 percentage points, relatively few non-partisan surveys of the race have been published. Historically, incumbents have enjoyed unusually large advantages in states with small populations, like Montana. Moreover, Mr Tester’s fundraising within the state—a good predictor of electoral performance—far exceeds that of his opponent, Tim Sheehy, an entrepreneur and political novice. If fresh polls confirm that Mr Tester is trailing badly, the model will probably lower his chance of victory from 38% to somewhere in the 20s—and possibly drag his party’s probability of winning the Senate down into that range as well.

民主党可能控制参议院的第二个原因是，该模型还没有准备好抹杀泰斯特。尽管最近的民调显示他下降了 6-8 个百分点，但公布的无党派竞选调查相对较少。从历史上看，在位者在蒙大拿州等人口较少的州享有异常大的优势。此外，泰斯特先生在州内的筹款活动——一个很好的选举表现预测指标——远远超过了他的对手、企业家和政治新手蒂姆·希希（Tim Sheehy）。如果新的民意调查证实泰斯特严重落后，该模型可能会将他获胜的几率从38%降低到20%左右，并可能将他的政党赢得参议院的可能性也拉低到这个范围内。

The final reason for hope for Democrats in the Senate is that a loss in Montana or Ohio is not necessarily the end of the story. Recent surveys put the party’s challengers to Republican incumbents in the pale-red states of Florida and Texas just a few points behind. And in a scenario that seems less outlandish with every poll, Deb Fischer, a Republican incumbent in Nebraska, appears to be in a remarkably tight race against Dan Osborn, a former union leader running as an independent.

民主党人在参议院抱有希望的最后一个原因是，在蒙大拿州或俄亥俄州的失败并不一定是故事的结局。最近的民意调查显示，该党在佛罗里达州和德克萨斯州等淡红色州对共和党现任议员的挑战者仅落后几个百分点。在每次民意调查中似乎都不那么古怪的情况下，内布拉斯加州的共和党现任议员黛布·菲舍尔（Deb Fischer）似乎与以独立人士身份参选的前工会领袖丹·奥斯本（Dan Osborn）展开了一场非常激烈的竞争。

The Democrats have not fielded a candidate in the contest, and Mr Osborn has rejected their endorsement—probably a wise move in a staunchly Republican state. But he is a fan of Bernie Sanders, a left-wing senator, and our model assumes that he would support a Democrat for majority leader. The past six polls of the race have all shown results between a slim two-point lead for Ms Fischer and a stunning five-point edge for Mr Osborn. Five of them were sponsored by Mr Osborn or groups supporting him, but an independent survey also showed him trailing by a single point. Our model gives Mr Osborn a 29% chance of victory—which is 29 percentage points more than Democrats would have expected earlier this year. That, in turn, gives Democrats a large boost in our forecast. If the model ignores partisan polling from Nebraska, the Republicans’ chance of controlling the Senate rises to 70%.

民主党尚未派出候选人参加竞选，奥斯本也拒绝了他们的支持——在一个坚定的共和党州，这可能是明智之举。但他是左翼参议员伯尼·桑德斯（Bernie Sanders）的粉丝，我们的模型假设他会支持民主党人竞选多数党领袖。过去六次竞选民意调查的结果都显示，菲舍尔以微弱优势领先 2 个百分点，而奥斯本以惊人的 5 个百分点优势领先。其中五项是由奥斯本先生或支持他的团体赞助的，但一项独立调查也显示他落后一个百分点。我们的模型显示奥斯本获胜的几率为 29%，比民主党今年早些时候的预期高出 29 个百分点。这反过来又大大提高了民主党人的预测。如果该模型忽略了内布拉斯加州的党派民意调查，共和党控制参议院的机会将上升到 70%。

Nonetheless, our model’s most confident prediction is that some Senate race, somewhere, will deliver a surprise. Large polling errors are common in Senate races. In 2020, for instance, Susan Collins of Maine, a Republican who trailed by around three points in polling averages, won re-election by ten points. There is a good chance, therefore, that a single surprising result could determine control of the chamber. Although Democrats’ probabilities of victory in Florida, Missouri, Nebraska and Texas are fairly low, ranging from 11% to 29%, the party pulls off an upset in at least one of these states in just over half of our simulations. Moreover, they do so in 47% of the scenarios in which either Mr Tester or Mr Brown loses, compensating for what would otherwise be a fatal defeat.

尽管如此，我们的模型最有把握的预测是，某个地方的参议院竞选将带来惊喜。较大的民意调查误差在参议院竞选中很常见。例如，在 2020 年，缅因州的共和党人苏珊·柯林斯 （Susan Collins） 在民调平均支持率上落后约 3 个百分点，但以 10 个百分点的优势赢得连任。因此，一个令人惊讶的结果很有可能决定对众议院的控制。尽管民主党在佛罗里达州、密苏里州、内布拉斯加州和德克萨斯州获胜的概率相当低，从 11% 到 29% 不等，但在我们的模拟中，该党至少在其中一个州取得了冷门。此外，在 47% 的 Tester 先生或 Brown 先生输掉的情况下，他们这样做了，以补偿否则将是致命的失败。

The contest for the House, where Republicans currently outnumber Democrats by just 220 to 212 (with three seats vacant), is even tighter. Democrats have a narrow lead of around two percentage points in “generic-ballot” surveys, which ask respondents which party they plan to support. They have also performed extremely well in special elections to replace departing House members, a strong indicator for normal elections that is not affected by polling biases. That gives them a slight edge, but one so slender that control of the lower chamber will probably come down to the specifics of particular districts.

众议院的竞争更加激烈，共和党人目前仅以 220 比 212 的比分超过民主党人（还有 3 个席位空缺）。民主党人在“通用投票”调查中以大约两个百分点的微弱优势领先，该调查询问受访者他们打算支持哪个政党。他们在取代即将离任的众议院议员的特别选举中也表现得非常出色，这是不受民意调查偏见影响的正常选举的有力指标。这给了他们一点优势，但这种优势是如此微弱，以至于对下议院的控制可能归结为特定选区的具体情况。

Gerrymandering, which used to give Republicans a big advantage in the House, is becoming more of a tie. On average, our model concludes that Democrats need to win the national popular vote only by a single point to secure a majority in the House. Although Republicans recently redrew districts to thwart three Democrats in North Carolina, they are expected to lose a seat in both Alabama and Louisiana, after the Supreme Court ordered redistricting to prevent the “packing” of black voters into a single district. Moreover, Democrats are on the offensive in New York. Even though the Democratic-controlled state legislature chose to enact only a mild redistricting following the party’s disastrous showing in the midterm elections of 2022, four Republican incumbents, all running in districts that voted Democratic in the presidential election of 2020, face tough races. On average, our model expects Democrats to win 19 of the state’s 26 seats, up from 15 two years ago.

过去让共和党在众议院占据巨大优势的不公正选区划分，现在正变得越来越像平局。平均而言，我们的模型得出的结论是，民主党只需要赢得全国普选一分即可确保在众议院获得多数席位。尽管共和党人最近在北卡罗来纳州重新划分选区以挫败三名民主党人，但在最高法院下令重新划分选区以防止黑人选民“挤”到一个选区后，预计他们将在阿拉巴马州和路易斯安那州失去一个席位。此外，民主党人在纽约州处于攻势。尽管民主党控制的州立法机构在该党在 2022 年中期选举中的灾难性表现后选择只进行温和的选区重划，但四名共和党现任议员都在 2020 年总统选举中投票给民主党的选区竞选，面临着艰难的竞争。平均而言，我们的模型预计民主党将赢得该州 26 个席位中的 19 个，高于两年前的 15 个。

In the past, centrist House candidates have tended to fare better than other factors would suggest and ideologically extreme ones worse. But since the start of Mr Trump’s presidency, this pattern appears to have faded. At any rate, several prominent moderates are trailing in local polls, including Jared Golden, a Democrat in a rural seat in Maine that Mr Trump carried in 2020, and Don Bacon, a Republican who represents a seat in Omaha, Nebraska, that plumped for Joe Biden. Our model is sceptical that enough voters will split their tickets for either to survive this time. In contrast, the model is more sanguine about Mary Peltola of Alaska and Marie Gluesenkamp Perez of Washington, both down-to-earth Democrats in red districts who enjoy comfortable fundraising advantages.

过去，中间派的众议院候选人往往比其他因素所暗示的要好，而意识形态极端的候选人则更糟。但自特朗普就任总统以来，这种模式似乎已经消失了。无论如何，几位著名的温和派在地方民调中落后，包括特朗普在 2020 年担任缅因州农村席位的民主党人贾里德·戈尔登 （Jared Golden），以及代表内布拉斯加州奥马哈一个席位的共和党人唐·培根 （Don Bacon），后者支持乔·拜登。我们的模型怀疑是否有足够多的选民会分票支持这一次。相比之下，该模型对阿拉斯加州的玛丽·佩尔托拉（Mary Peltola）和华盛顿州的玛丽·格鲁森坎普·佩雷斯（Marie Gluesenkamp Perez）持乐观态度，这两位都是来自红色选区的脚踏实地的民主党人，享有舒适的筹款优势。

The battle for the House is most likely to be determined in California. Although America’s most populous state is reliably Democratic overall, a non-partisan commission draws its districts, ensuring that Republicans get a fair shake. Six of the nine House races that our model calculates are most likely to deliver the decisive 218th seat for the victorious party are in California: four in the urban sprawl surrounding Los Angeles and two in the Central Valley. Of these, five are majority-minority with large Hispanic or Asian populations, and are held by Republicans. If the gains Mr Trump has made in polls with non-white voters translate into support for Republicans lower down the ballot, House Democrats will probably meet their Waterloo in deep-blue California. But if Ms Harris, who is herself a Californian of both Jamaican and South Asian descent, can claw back some of these voters en route to the presidency, Republicans will probably lose the House, too.

众议院之争最有可能在加利福尼亚州决定。尽管美国人口最多的州总体上是可靠的民主党，但一个无党派的委员会负责划分选区，确保共和党人得到公平的待遇。在我们的模型计算出的 9 场众议院选举中，有 6 场最有可能为获胜的政党带来决定性的第 218 个席位：4 场在洛杉矶周围的城市扩张中，2 场在中央山谷。其中，5 个是拥有大量西班牙裔或亚裔人口的少数对多数席位，由共和党人担任。如果特朗普在非白人选民民调中取得的胜利转化为对共和党人在选票中较低的支持率，那么众议院民主党人可能会在深蓝色的加州遇到他们的滑铁卢。但是，如果哈里斯本人是牙买加和南亚裔的加利福尼亚人，能够在竞选总统的道路上夺回其中一些选民，共和党人也可能会失去众议院。

A president can do a lot by fiat, without Congress’s approval. And if the president’s party controls the Senate it can push through judicial nominations, even if the House is more hostile territory. Even so, the congressional toss-up compounds the uncertainty of this year’s dead-heat presidential election. ■

总统可以不经国会批准，通过法定手段做很多事情。如果总统所在的政党控制了参议院，它就可以推动司法提名，即使众议院是更具敌意的领域。即便如此，国会的争论加剧了今年势均力敌的总统选举的不确定性。■