Sacks predicted that within about three months of Aug. 16, 2024, Kamala Harris would not be able to keep running a “vibes only,” low‑interview, low‑substance campaign as a seeming moderate, because her more progressive policy views would become clear to voters.

There is evidence supporting his view that her progressive policy orientation became more visible:

• In mid‑August and September 2024, the Harris campaign rolled out an “Agenda to Lower Costs for American Families” and a broader economic plan (“A New Way Forward for the Middle Class”) featuring a federal ban on grocery price gouging, large expansions of the Child Tax Credit and Earned Income Tax Credit, substantial new housing subsidies, and other redistributive measures—policies widely covered in mainstream and specialist outlets and generally characterized as aggressive, interventionist economics. (democracyinaction.us)
• Fact‑checking and analysis pieces treated the price‑gouging ban as a central plank of her campaign, noting that her ads referencing it ran at scale, and economic commentators across the spectrum debated whether it amounted to de facto price controls. (factcheck.org)
• The Dispatch, which closely tracked her platform, described these domestic proposals as “very progressive” while noting that she projected a surface image of moderation and normalcy. (thedispatch.com)
• Polling in early September 2024 (NYT/Siena, Marist and others) found a plurality of voters saying Harris was “too liberal or progressive”, with roughly 44–48% labeling her too liberal and around 41–43% saying she was “about right.” (newsmax.com) This suggests that many voters did see her as left‑of‑center ideologically, not as a centrist.

But there is also strong evidence against his claim that she would be forced to abandon a vibes‑heavy, low‑interview, low‑detail strategy:

• Through September and into October 2024, reporters and analysts repeatedly noted that Harris had done very few sit‑down interviews, no press conferences, and tightly choreographed appearances. An ECFR “Letter from Washington” described her as “almost allergic to policy specifics,” running a “vibes” campaign with only one network interview and no pressers, and speeches “heavy on mood and light on policy.” (ecfr.eu)
• Media reports and commentary during the campaign (e.g., Daily Caller, Free Beacon, and others summarizing Politico/CNN reporting) criticized the Harris–Walz operation for a “basement” or low‑exposure strategy, saying both candidates were kept on a very limited interview diet and that this backfired at the debate. (dailycaller.com)
• Post‑election insider accounts and donor grumbling in early 2025 likewise faulted her for being extremely risk‑averse and doing too few interviews, saying “there was nothing to peel the onion back for people.” (pagesix.com) Even Donald Trump’s later “advice” to her—that she needed to start giving interviews—explicitly framed her 2024 campaign as unusually guarded with the press. (nypost.com)
• Broader campaign analyses (e.g., the Boston Globe and ECFR) described the overall 2024 race as driven by emotions and “vibes,” with neither Trump nor Harris offering a fully fleshed‑out policy program, reinforcing that her public image never moved far from a vibes‑heavy approach. (bostonglobe.com)

Putting this together:

• Harris did not really abandon the low‑interview, carefully stage‑managed, rhetoric‑heavy style Sacks was criticizing; contemporaneous coverage and later postmortems agree that she stuck with a vibes‑forward, low‑risk media strategy through Election Day.
• At the same time, she did put forward a set of clearly progressive economic proposals (price‑gouging ban, large child‑benefit expansions, housing subsidies, etc.) that were widely reported and debated, and polling shows many voters saw her as “too liberal or progressive.”

Because the prediction mixes several subjective elements—how “vibes‑only” the campaign remained, how “moderate” she looked, and how “clear” her progressive positions became to the public—and the empirical record cuts both ways, reasonable observers could plausibly argue that Sacks was either vindicated (on ideological visibility) or refuted (on the sustainability of a vibes‑heavy, low‑interview strategy). For that reason, the outcome is best categorized as ambiguous rather than clearly right or wrong.