Sacks predicted that:

1. Donald Trump would pursue election court challenges for a few weeks after the election but effectively end them by U.S. Thanksgiving 2020 (November 26, 2020), meaning the contest of the result would be over by then.
2. Courts would ultimately rule against Trump or throw out his cases.

What actually happened:

• Trump and his allies continued significant legal efforts after Thanksgiving. For example, on November 27, 2020 (the day after Thanksgiving), the Third Circuit Court of Appeals rejected the Trump campaign’s attempt to undo Pennsylvania’s vote certification, showing the campaign was still actively litigating key challenges beyond Thanksgiving. (en.wikipedia.org)
• Trump’s broader effort to overturn the election ran from early November well into December 2020 and January 2021, involving dozens of lawsuits, pressure on state officials, and attempts to get the Supreme Court to intervene; this was not effectively “over” by Thanksgiving. (en.wikipedia.org)
• A major post-Thanksgiving legal push was Texas v. Pennsylvania, filed December 8, 2020, at the U.S. Supreme Court, seeking to invalidate Biden’s wins in four states. The Court dismissed the case on December 11, 2020 for lack of standing—another prominent defeat, but clearly showing that the legal contest continued well beyond Thanksgiving. (en.wikipedia.org)
• Overall, Trump and his allies filed 60+ lawsuits related to the 2020 election and did not win any that could change the outcome; courts repeatedly dismissed or ruled against them, matching the part of Sacks’ prediction that courts would ultimately rule against Trump’s side. (en.wikipedia.org)

Assessment:

• The timing and “end by Thanksgiving” component of the prediction was clearly wrong: high‑profile court challenges and broader legal/political efforts to overturn the election were still very much active in December and even into January. (en.wikipedia.org)
• The courts‑will‑rule‑against-him component was correct, but it was coupled to the stronger claim that the contest would effectively be over by Thanksgiving.

Because the key claim about when Trump’s challenges would effectively end was false, the prediction as stated is best judged wrong overall, despite being right that the courts would ultimately reject his efforts.