At the start of the war registered voters under 30 preferred Mr Biden to Mr Trump by a 28-point margin. In June the same group said they favoured Mr Biden by an average of 20 points.
加沙戰爭開始時,拜登在30歲以下的登記選民中領先28個百分點。6月份,在該年齡組中領先20個百分點。
The decline in Mr Biden's popularity may not be dramatic, but it could be significant in a close race. The available data are unclear about whether Gaza is the cause, however.
拜登支持率的下降可能并不顯著,但在勢均力敵的競選中,影響可能很大。然而,現有數據尚不清楚加沙戰爭是否是罪魁禍首。
Other White House policies unpopular with young people, such as the forced sale of TikTok within a year that the House of Representatives passed in March with Mr Biden's support, may also matter.
白宮其他不受年輕人歡迎的政策,例如眾議院3月份在拜登支持下通過的在一年內強制出售TikTok的政策,也可能很重要。
According to a poll in May from Generation Lab only 13% of college students say that the conflict in the Middle East is one of their three most important issues, despite a tumultuous springtime of protests on many American campuses.
根據Generation Lab五月份的一項民調顯示,盡管許多美國校園在春季爆發了抗議活動,但只有13%的大學生表示中東沖突是他們最重要的三個問題之一。
The evidence is clearer about two other problems Mr Biden has with young voters.
拜登在年輕選民中面臨的另外兩個問題的證據更清楚。
One is his low standing with independents. The president's current polling advantage among young Democrats is the same as it was at this stage in 2020.
一是他在獨立人士中的地位低下。總統目前在年輕民主黨人中的民調優勢與2020年同期相同。
Yet he is attracting a scant 27% of young independents. (Mr Trump and Robert F. Kennedy junior are performing even worse; and 16% of young independents tell pollsters they are undecided.)
然而,他只吸引了27%的年輕獨立人士。(特朗普和小羅伯特·肯尼迪的表現更差;16% 的年輕獨立人士告訴民意調查員,他們尚未決定。)
Young independent voters are especially fuzzy about Mr Biden's policies.
年輕的獨立選民尤其不理解拜登的政策。
That points to Mr Biden's second problem: he is struggling on TikTok, where one-third of Americans under 30 get their news, according to a poll last year.
這指出了拜登的第二個問題:他在TikTok上苦苦掙扎,根據去年的一項民調,三分之一的30歲以下美國人通過TikTok獲取新聞。
Mr Trump joined the platform only three weeks ago but has already garnered 252m views. His content generates more engagement than Mr Biden's.
特朗普加入該平臺僅三周,但已經獲得了2.52億次觀看。他的內容比拜登的更吸引人。
"Content around Biden just doesn't pop off on TikTok," says Ben Darr, of CredoIQ, a TikTok-analytics firm.
“圍繞拜登的內容在TikTok上并不受歡迎,”TikTok分析公司CredoIQ創始人本·達爾(Ben Darr)說道。
"It's not inflammatory, it's not counterculture…and that's what the TikTok algorithm is looking for." In terms of issues, young voters are not so different from everyone else.
“它不是煽動性的,也不是反主流文化……而這正是TikTok算法所尋找的。”在問題方面,年輕選民與其他人并無太大不同。
In April's Harvard Youth Poll, the three most important issues they cited were inflation, health care and housing. These are priorities for all voters.
四月份的哈佛青年民調顯示,他們提到的三個最重要的問題是通貨膨脹、醫療保健和住房。這些都是所有選民優先考慮的事項。
Young Republicans prioritise immigration more than their Democratic counterparts, while those Democrats prioritise women's reproductive rights.
年輕的共和黨人比民主黨人更重視移民問題,而民主黨人則優先考慮婦女的生育權。
Overall, Mr Biden's vulnerability with young voters is not a consequence of the policies he promotes.
總體而言,拜登在年輕選民中的弱勢地位并不是他所推行的政策的結果。
According to a recent YouGov poll, the great majority of policies preferred by young Democrats and independents are ones that Mr Biden favours and Mr Trump rejects.
根據最近的輿觀民調顯示,年輕民主黨人和獨立人士所青睞的絕大多數政策都是拜登支持而特朗普反對的政策。
Overwhelming majorities say theywant expanded background checks for all gun purchases and increased federal funding for affordable housing and the Affordable Care Act, for instance.
絕大多數人表示,他們希望擴大對所有槍支購買的背景調查,并增加聯邦對經濟適用房和《平價醫療法案》的資助。
Mr Biden's boomer backers may wring their hands over young voters' seeming apathy about Mr Trump's xenophobic populism.
拜登的嬰兒潮一代支持者可能會對年輕選民對特朗普排外民粹主義的冷漠感到不安。
Yet the reality is that for a growing share of young voters, Trumpism is the norm.
然而現實是,對于越來越多的年輕選民來說,特朗普主義是常態。
This year's youngest eligible voter was just nine years old when Mr Trump declared that Mexicans were rapists as he launched his 2016 campaign.
今年最年輕的合格選民只有9歲,當時特朗普在2016年競選期間宣稱墨西哥人是強奸犯。
And that same voter was only in their first year of high school as his presidency concluded with hundreds of his supporters attacking the Capitol.
而當特朗普的總統任期結束時,數百名支持者襲擊國會大廈,這位選民才剛剛上高中一年級。
Younger voters, like generations before them, are focused on their own futures. Quite reasonably, they want to know what Mr Biden will do for them if he is re-elected.
年輕選民和上一代人一樣,關注自己的未來。他們自然想知道拜登如果連任會為他們做些什么。