Sacks argued that Kamala Harris’s August 2024 polling “sugar high” would end once she released substantive policy proposals—specifically including measures like grocery price controls—triggering a significant correction downward in her standing vs. Donald Trump before November.

1. Timing and nature of the policy proposals
Harris did, in fact, roll out economic proposals in August 2024, including a call for a federal ban on corporate “price gouging” on groceries and an expanded child tax credit. These were framed as tools to lower grocery prices and were widely covered as part of her August economic agenda. (amp.cnn.com) This matches the kind of grocery price‑control proposal Sacks was referring to.

2. What happened to her polls after the proposals
Available polling and averages do not show a large, sustained downturn in Harris’s relative standing vs. Trump following the August rollout:

• A compiled table of national polling for 2024 shows that in August, Harris and Trump were roughly tied nationally (both around 47–48%). In September, Harris’s position improved, with averages showing her about 1–3 points ahead of Trump (e.g., Harris 48–49% vs. Trump 46–47%), not worse. In October, the race tightened back to roughly even, but not to a clear or durable Trump lead. (en.wikipedia.org)
• Individual poll and model snapshots in mid‑September—after the economic proposals—show Harris still gaining or holding a lead. For example, a Newsmax summary of Nate Silver’s model and RealClearPolitics averages around Sept. 16–17 had Harris leading Trump nationally by about 2 points (FiveThirtyEight: ~48.5–46.3; RCP: ~49.1–47.3), and a large Morning Consult poll at that time showed Harris +6 (51–45). (newsmax.com) This is opposite of an immediate “big correction” down.

3. Position just before Election Day
By late October and the final week before the election, national polls and aggregators still showed an extremely close race with Harris generally a hair ahead, not in a clearly corrected slump:

• A Guardian analysis of national polling averages found that throughout October 2024, Harris polled about 1–2 points above Trump, with the gap narrowing to about 1 point by Oct. 31. (theguardian.com)
• On the day before the election, a Yahoo News summary of three major aggregators (Silver Bulletin, FiveThirtyEight, New York Times) showed Harris leading Trump nationally by about 0.5–1 point in each average—still a small Harris edge, not a Trump lead. (yahoo.com)
• The Wikipedia compilation of late‑October polls lists many high‑quality national surveys with Harris at roughly 49–51% and Trump at roughly 46–49%, again indicating a neck‑and‑neck race with Harris often marginally ahead, not a large correction against her. (en.wikipedia.org)

4. Final outcome vs. pre‑election “correction” story
In the actual result, Trump won the popular vote by about 49.8% to 48.3% (roughly Trump +1.5), while final national polls generally had Harris at about 48–49% and Trump around 47–48%. (en.wikipedia.org) Post‑election analyses emphasized that polls underestimated Trump’s support, as in prior cycles, rather than documenting a major pre‑election plunge in Harris’s standing triggered by her August policy rollout. (politico.com)

Putting this together:

• Harris did enjoy an August surge.
• She did release grocery price‑gouging/price‑control‑style proposals in August.
• But after those proposals, her polling relative to Trump mostly held or improved through September, and by late October she still had a tiny lead in most national aggregates. There is no evidence of the large, proposal‑driven “big correction” in polling that Sacks forecast; instead, the race gradually tightened and then the polls slightly missed in Trump’s favor.

Because the central claim—that the rollout of those policy proposals would mark the start of a significant pre‑election decline in Harris’s relative polling vs. Trump—did not materialize in the polling data, this prediction is best classified as wrong.