副总统卡玛拉·哈里斯面临一连串的种族主义攻击自从乔·拜登总统退出总统竞选以来。7月31日，前总统唐纳德·特朗普在全国黑人记者协会年会上煽风点火，当时他谎称哈里斯“碰巧最近才变黑”。特朗普竞选团队已经双倍下注重复那些指控几个倍在过去的一个月里。

　　如果这些攻击是为了削弱哈里斯的势头，然而，他们没有成功。特朗普显然已经失落的土地自他在NABJ露面以来的民意调查中，他在活动中的言论受到了新闻媒体、民主党人甚至一些高调的共和党人。事实证明，这是可以预见的。调查数据和政治学研究告诉我们，特朗普的言论可能会损害他的总统竞选有三大原因。

　　特朗普正在强调他最大的负债之一

　　首先，或许也是最重要的一点，特朗普对哈里斯种族身份的攻击让人们重新关注他最薄弱的问题。我回溯到2020年6月例如，特朗普经常因为处理种族关系而获得最低的支持率。在2019年的调查中，特朗普在种族问题上的净支持率(批准减去不批准)一直在30个百分点左右。

　　这些压倒性的负面评价在他的总统任期内持续不断。选民给了特朗普在种族关系上的得分比其他任何主要问题都低在一个2020年10月YouGov/雅虎新闻调查。在调查的问题上，拜登以高达22个百分点的优势(53%对31%)领先特朗普，该问题是关于哪位候选人在总统任期内处理种族关系方面做得更好——在2020年竞选活动的九个最突出的问题上，他比特朗普最大的优势。

　　然而，选民几乎总是更积极地评价前总统的表现回想起来，特朗普也经历过类似的“怀旧肿块回顾他对种族和其他几个问题的处理。他在总统任期内处理种族关系的净支持率仅为-11%2024年4月纽约时报/锡耶纳学院民意调查。同样，拜登在种族问题上对特朗普的优势在2008年已经缩小到只有10个百分点2024年6月萨福克大学/今日美国调查.

　　因此，特朗普及其盟友对哈里斯混血儿背景的攻击有可能让怀旧的选民想起他在总统任期内不得人心的种族关系方针。他们可能会让特朗普在种族问题上的糟糕表现成为更突出的投票问题，从而给特朗普带来更大的问题。一些政治学研究认为总统竞选的主要目标是强调有利的问题，这样他们就可以更多地影响美国人的投票。

　　然而，对哈里斯的种族主义攻击实际上适得其反。而不是强调他比民主党人更有优势的问题，例如移居和通货膨胀，特朗普对哈里斯种族背景的错误攻击使人们的注意力重新集中在他最大的政治责任之一上。根据这一论点，一个聪明的实验嵌入到一个新的费尔利·迪金森大学民意调查发现哈里斯对特朗普的领先优势在那些事先准备好考虑候选人的种族和族裔的选民中显著上升。

　　将美国黑人团结到哈里斯身边

　　当哈里斯参加总统竞选时，她在黑人选民中并不是特别受欢迎。如同萨曼莎·坎迪和我在七月写道在他们执政的前三年里，黑人对她的评价明显低于对拜登的评价。

　　可以肯定的是，哈里斯在黑人登记选民中的支持率在2004年从71%迅速上升到82%Civiqs的每日跟踪数据她成为该党的假定提名人后不久。但是538分析7月21日至8月17日进行的民调显示，她在黑人受访者中的支持率仍落后于拜登。黑人受访者对哈里斯的支持率也比他们在2007年对前总统巴拉克·奥巴马的支持率低16个百分点YouGov/经济学人民意调查(分别为69%和85%)是在特朗普出席NABJ前几天进行的。

　　我和Canty的研究发现，哈里斯在黑人选民中的受欢迎程度远远低于奥巴马，黑人选民在种族团结方面得分最高，例如非常喜欢黑人，认为种族对他们的身份非常重要。这对特朗普来说是个坏消息，因为这些有种族意识的黑人选民也最有可能被针对哈里斯的种族主义攻击所动摇。

　　政治学研究表明，在种族团结方面得分最高的选民既是最快察觉到歧视针对他们团体的成员在政治上为他们辩护。如果说有什么不同的话，那么，对哈里斯的种族主义攻击应该有助于巩固她在同样具有种族意识的黑人选民中的支持，这些选民在她担任副总统的大部分时间里对她只有敌意。

　　动员同情种族的白人

　　对哈里斯的种族主义攻击也可能适得其反，因为美国白人认为反黑人歧视是美国的一个主要问题。毕竟，奥巴马通过激活来自这些富有种族同情心的美国白人的空前强大的支持.

　　自奥巴马担任总统以来，种族自由主义已经成为美国政治中一股更大的政治力量。认为种族歧视和系统性种族主义是黑人成功的主要障碍的美国白人比例急剧增加在特朗普政府期间—尤其是白人民主党人.

　　但民主党人远不是唯一同情受到不公平对待的美国黑人的人。A新书韦尔斯利学院政治学家詹妮弗·丘迪的《论种族态度》表明，大多数白人对经历过种族歧视的美国黑人表示“大量”或“很多”同情。

　　因此，对哈里斯公开的种族主义攻击只会让她在这群同情面临种族歧视的黑人的白人当中成为一个更有同情心的人物。的确，社会科学研究长期以来一直认为，明确的种族主义竞选呼吁是无效的，因为它们违反了大多数美国白人对种族平等规范和原则的承诺。和一个最近的书来自威廉姆斯学院的政治学家马修·托克西指出，反驳对黑人候选人的种族主义攻击往往会动员同情种族主义的白人的支持。

　　* * *

　　有其他原因为什么对哈里斯的种族主义攻击也可能适得其反。但是，不管这里起作用的确切机制是什么，关于问题优势、黑人选民和种族同情的白人选民的数据和研究都强烈表明，特朗普对哈里斯提出种族主义上诉没有任何好处——特别是当他已经这样做了在有种族偏见的白人中间最大化了他的选票份额2016年和2020年的选举。

　　3 reasons why racist attacks on Harris could backfire

　　Vice President Kamala Harrishas faced a barrage of racist attackson her qualifications and background since President Joe Biden withdrew from the presidential campaign. On July 31, former President Donald Trump fanned those flames at the National Association of Black Journalists' annual convention when hefalsely claimed that Harris "happened to turn Black" only recently. The Trump campaign hasdoubled downon those accusations, too, repeating themseveraltimesover the past month.

　　If these attacks were meant to blunt Harris’s momentum, however, they haven’t worked. Trump has clearlylost groundin the polls since his NABJ appearance, and his rhetoric at the event was heavily criticized by the news media, Democrats and evensome high-profile Republicans. It turns out, this was predictable. Survey data and political science research tells us there are three big reasons why Trump’s remarks will likely hurt his presidential campaign.

　　Trump is emphasizing one of his biggest liabilities

　　First, and perhaps most importantly, Trump's attacks on Harris's racial identity refocuses attention on arguably his weakest issue. Inoted back in June 2020, for example, that Trump regularly received his lowest issue approval ratings for his handling of race relations. Trump's net approval ratings (approval minus disapproval) on race were consistently around 30 percentage points underwater in 2019 surveys.

　　Those overwhelmingly negative assessments continued throughout his presidency. Voters gave Trumplower scores on race relations than on any other major issuein anOctober 2020 YouGov/Yahoo News poll. Biden led Trump by a whopping 22-point margin (53 percent to 31 percent) on the survey's question about which candidate would do a better job of handling race relations as president — his biggest advantage over Trump across nine of the most salient issues in the 2020 campaign.

　　Voters, however, almost alwaysrate ex-presidents' performances more positivelyin retrospect, and Trump has experienced a similar "nostalgia bump" in retrospective approval of his handling of race and several other issues. His net approval rating for how he handled race relations during his presidency was only -11 points in anApril 2024 New York Times/Siena College poll. Likewise, Biden's advantage over Trump on the issue of race had dwindled to just 10 points in aJune 2024 Suffolk University/USA Today survey.

　　Attacks on Harris's biracial background by Trump and his allies, therefore, run the risk of reminding nostalgic voters of his presidency's unpopular approach to race relations. They could pose an even bigger problem for Trump by making his poor performance on race a more prominent voting issue.Some political science researchcontends that the main goal of presidential campaigns is to emphasize advantageous issues so that they might factor more heavily into Americans' votes.

　　Racist attacks against Harris, however, effectively do the exact opposite. Instead of emphasizing issues on which he has an advantage over the Democrats, such asimmigrationandinflation, Trump's false attacks on Harris's racial background refocus attention on one of his biggest political liabilities. In keeping with that contention, a clever experiment embedded in a newFairleigh Dickinson University pollfound that Harris's lead against Trump grew significantly among voters who were primed to think about the candidates' race and ethnicity ahead of time.

　　Rallying Black Americans to Harris

　　Harris was not particularly popular among Black voters when she jumped into the presidential race. AsSamantha Canty and I wrote in July, Black people rated her significantly less favorably than they rated Biden throughout the first three years of their administration.

　　To be sure, Harris's favorability rating among Black registered voters quickly surged from 71 to 82 percent inCiviqs's daily tracking datasoon after she became her party's presumptive nominee. But a538 analysisof polls conducted July 21-Aug. 17 still showed her trailing Biden's 2020 vote margins among Black respondents. Black respondents also rated Harris 16 points less favorably than they rated former President Barack Obama in aYouGov/The Economist poll(69 and 85 percent, respectively) conducted just a few days before Trump's NABJ appearance.

　　My research with Canty found that Harris underperforms Obama's popularity by the widest margins among Black voters who score highest in measures of racial solidarity, such as rating Black people very favorably and saying race is very important to their identities. That's bad news for Trump since these racially conscious Black voters are also the most likely to be countermobilized by racist attacks against Harris.

　　Political science research shows that voters who score highest in measures of racial solidarity are both thequickest to perceive discriminationagainst members of their group and topolitically rally in defense of them. If anything, then, racist attacks on Harris should help solidify her support among the same racially conscious Black voters who had only felt lukewarmly toward her throughout most of her vice presidency.

　　Mobilizing racially sympathetic whites

　　Racist attacks against Harris could also backfire by countermobilizing white Americans who think anti-Black discrimination is a major problem in the U.S. After all, Obama offset race-based opposition in part by activatingunprecedentedly strong support from such racially sympathetic white Americans.

　　Racial liberalism has become an even bigger political force in American politics since Obama's presidency. The share of white Americans who viewed racial discrimination and systemic racism as major impediments to Black successincreased dramaticallyduring the Trump administration —especially among white Democrats.

　　But Democrats are far from the only ones who empathize with Black Americans who are treated unfairly. Anew bookon racial attitudes by Wellesley College political scientist Jennifer Chudy shows that most white people express either "a great deal" or "a lot" of sympathy with Black Americans who've experienced tangible instances of racial discrimination.

　　Overtly racist attacks against Harris should, therefore, only make her a more sympathetic figure among this large share of whites who empathize with Black people facing racial discrimination. Indeed,social science researchhas long suggested that explicitly racist campaign appeals are ineffective precisely because they violate most white Americans' commitment to norms and principles of racial equality. And arecent bookfrom Williams College political scientist Matthew Tokeshi shows that rebutting racist attacks against Black candidates tends to mobilize support from racially sympathetic whites.

　　* * *

　　There areother reasonswhy racist attacks against Harris might backfire as well. But regardless of the exact mechanism at play here, the data and research on issue advantages, Black voters and racially sympathetic white voters strongly suggest that there just isn't an upside for Trump to employing racist appeals against Harris — especially when he had alreadymaximized his vote share among racially prejudiced whitesin the 2016 and 2020 elections.